WorldWideScience

Sample records for electron bombardment ion

  1. Electron emission from Inconel under ion bombardment

    International Nuclear Information System (INIS)

    Alonso, E.V.; Baragiola, R.A.; Ferron, J.; Oliva-Florio, A.

    1979-01-01

    Electron yields from clean and oxidized Inconel 625 surfaces have been measured for H + ,H 2 + ,He + ,O + and Ar + ions at normal incidence in the energy range 1.5 to 40 keV. These measurements have been made under ultrahigh vacuum and the samples were freed of surface contaminants by bombarding with high doses of either 20 keV H 2 + or 30 keV Ar + ions. Differences in yields of oxidized versus clean surfaces are explained in terms of differences in the probability that electrons internally excited escape upon reaching the surface. (author)

  2. Electron emission from molybdenum under ion bombardment

    International Nuclear Information System (INIS)

    Ferron, J.; Alonso, E.V.; Baragiola, R.A.; Oliva-Florio, A.

    1981-01-01

    Measurements are reported of electron emission yields of clean molybdenum surfaces under bombardment with H + , H 2 + , D + , D 2 + , He + , N + , N 2 + , O + , O 2 + , Ne + , Ar + , Kr + and Xe + in the wide energy range 0.7-60.2 keV. The clean surfaces were produced by inert gas sputtering under ultrahigh vacuum. The results are compared with those predicted by a core-level excitation model. The disagreement found when using correct values for the energy levels of Mo is traced to wrong assumptions in the model. A substantially improved agreement with experiment is obtained using a model in which electron emission results from the excitation of valence electrons from the target by the projectiles and fast recoiling target atoms. (author)

  3. Direct and Recoil-Induced Electron Emission from Ion-Bombarded Solids

    DEFF Research Database (Denmark)

    Holmen, G.; Svensson, B.; Schou, Jørgen

    1979-01-01

    The kinetic emission of secondary electrons from ion-bombarded solid surfaces is split into two contributions, a direct one caused by ionizing collisions between the bombarding ion and target atoms, and an indirect one originating from ionizing collisions undergone by recoil atoms with other target...... atoms. The direct contribution, which has been treated by several authors in previous studies, shows a behavior that is determined primarily by the electronic stopping power of the bombarding ion, while the indirect contribution is nonproportionally related to the nuclear stopping power. This latter...

  4. Measurement of electron emission due to energetic ion bombardment in plasma source ion implantation

    Science.gov (United States)

    Shamim, M. M.; Scheuer, J. T.; Fetherston, R. P.; Conrad, J. R.

    1991-11-01

    An experimental procedure has been developed to measure electron emission due to energetic ion bombardment during plasma source ion implantation. Spherical targets of copper, stainless steel, graphite, titanium alloy, and aluminum alloy were biased negatively to 20, 30, and 40 kV in argon and nitrogen plasmas. A Langmuir probe was used to detect the propagating sheath edge and a Rogowski transformer was used to measure the current to the target. The measurements of electron emission coefficients compare well with those measured under similar conditions.

  5. Excited-atom production by electron and ion bombardment of alkali halides

    International Nuclear Information System (INIS)

    Walkup, R.E.; Avouris, P.; Ghosh, A.P.

    1987-01-01

    We present experimental results on the production of excited atoms by electron and ion bombardment of alkali halides. For the case of electron bombardment, Doppler shift measurements show that the electronically excited atoms have a thermal velocity distribution in equilibrium with the surface temperature. Measurements of the absolute yield of excited atoms, the distribution of population among the excited states, and the systematic dependence on incident electron current and sample temperature support a model in which the excited atoms are produced by gas-phase collisions between desorbed ground-state atoms and secondary electrons. In contrast, for the case of ion bombardment, the excited atoms are directly sputtered from the surface, with velocity distributions characteristic of a collision cascade, and with typical energies of --10 eV

  6. Surface roughening under ion bombardment

    International Nuclear Information System (INIS)

    Bhatia, C.S.

    1982-01-01

    Ion bombardment can cause roughening of a surface. Inadequate step coverage and poor adhesion of films on such surfaces are of concern. An extreme case of surface roughening results in cone formation under ion bombardment. The results of the investigation, using scanning electron microscopy, is discussed in terms of the role of (a) embedded particles, (b) impurities and (c) surface migration in cone formation on the target surface. (Auth.)

  7. Ion bombardment modification of surfaces

    International Nuclear Information System (INIS)

    Auciello, O.

    1984-01-01

    An historical overview of the main advances in the understanding of bombardment-induced surface topography is presented. The implantation and sputtering mechanisms which are relevant to ion bombardment modification of surfaces and consequent structural, electronic and compositional changes are described. Descriptions of plasma and ion-beam sputtering-induced film formation, primary ion-beam deposition, dual beam techniques, cluster of molecule ion-beam deposition, and modification of thin film properties by ion bombardment during deposition are presented. A detailed account is given of the analytical and computational modelling of topography from the viewpoint of first erosion theory. Finally, an account of the possible application and/or importance of textured surfaces in technologies and/or experimental techniques not considered in previous chapters is presented. refs.; figs.; tabs

  8. Suppression secondary electrons from target surface under pulsed ion beams bombardment

    International Nuclear Information System (INIS)

    Yang Zhen; Peng Yufei; Long Jidong; Lan Chaohui; Dong Pan; Shi Jinshui

    2012-01-01

    The producing mechanism of secondary electrons from target surface under ion beams bombardment is discussed. Several methods to suppress the secondary electrons in special vacuum devices and their advantages and disadvantages are introduced. The ways of using self-bias and curved surface target are proposed and verified in the experiment. The results show that the secondary electrons can be effectively suppressed when the self-bias is larger than 80 V. The secondary electron yield decreases by using curved surface target instead of flat target. The secondary electron yield calculated from the experimental data is about 0.67, which is slightly larger than the value (0.58) from the literature due to the impurities of the ion beam and target surface. The effect of suppressing the electron countercurrent by the self-bias method is analyzed. The result shows that the self-bias method can not only suppress the secondary electrons from target surface under ion beams bombardment, but also suppress the electron countercurrent resulting from the instability of the pulsed power source. (authors)

  9. Ion induced electron emission statistics under Agm- cluster bombardment of Ag

    Science.gov (United States)

    Breuers, A.; Penning, R.; Wucher, A.

    2018-05-01

    The electron emission from a polycrystalline silver surface under bombardment with Agm- cluster ions (m = 1, 2, 3) is investigated in terms of ion induced kinetic excitation. The electron yield γ is determined directly by a current measurement method on the one hand and implicitly by the analysis of the electron emission statistics on the other hand. Successful measurements of the electron emission spectra ensure a deeper understanding of the ion induced kinetic electron emission process, with particular emphasis on the effect of the projectile cluster size to the yield as well as to emission statistics. The results allow a quantitative comparison to computer simulations performed for silver atoms and clusters impinging onto a silver surface.

  10. Ion Back-Bombardment of GaAs Photocathodes Inside DC High Voltage Electron Guns

    CERN Document Server

    Grames, Joseph M; Brittian, Joshua; Charles, Daniel; Clark, Jim; Hansknecht, John; Lynn Stutzman, Marcy; Poelker, Matthew; Surles-Law, Kenneth E

    2005-01-01

    The primary limitation for sustained high quantum efficiency operation of GaAs photocathodes inside DC high voltage electron guns is ion back-bombardment of the photocathode. This process results from ionization of residual gas within the cathode/anode gap by the extracted electron beam, which is subsequently accelerated backwards to the photocathode. The damage mechanism is believed to be either destruction of the negative electron affinity condition at the surface of the photocathode or damage to the crystal structure by implantation of the bombarding ions. This work characterizes ion formation within the anode/cathode gap for gas species typical of UHV vacuum chambers (i.e., hydrogen, carbon monoxide and methane). Calculations and simulations are performed to determine the ion trajectories and stopping distance within the photocathode material. The results of the simulations are compared with test results obtained using a 100 keV DC high voltage GaAs photoemission gun and beamline at currents up to 10 mA D...

  11. Study and realisation of an ion source obtained by electronic bombardment - experimentation with phosphorus

    International Nuclear Information System (INIS)

    Schneider, Philippe

    1979-01-01

    This research thesis reports the study and development of an ion source by electronic bombardment. In order to solve some practical difficulties (cathode destruction, source instability, and so on), the design of each component has been very careful, notably for the electron gun. The author first briefly discusses the exiting ionisation processes, gives a list of ion which can be produced, with a focus on phosphorus for which the ionisation cross section is defined and assessed. After an assessment of different ionisation processes, and an indication of performance of the best existing sources, the author explains the choice for a totally different process. In the second part, he describes the experimental device, and particularly the electron gun as its design has been an important part of this research work. The source operation is described and its characteristics and performance are studied. Finally, the author outlines that some improvements are still possible to obtain a totally exploitable source [fr

  12. Erosion of volatile elemental condensed gases by keV electron and light-ion bombardment

    International Nuclear Information System (INIS)

    Schou, J.

    1991-11-01

    Erosion of the most volatile elemental gases by keV electron and light-ion bombardment has been studied at the experimental setup at Risoe. The present work includes frozen neon, argon, krypton, nitrogen, oxygen and three hydrogen isotopes, deuterium, hydrogen deuteride and hydrogen. The yield of these condensed gases has been measured as a function of film thickness and primary energy for almost all combinations of primary particles (1-3 keV electrons, 5-10 keV hydrogen- and helium ions) and ices. These and other existing results show that there are substantial common features for the sputtering of frozen elemental gases. Within the two groups, the solid rare gases and the solid molecular gases, the similarity is striking. The hydrogenic solids deviate in some respects from the other elements. The processes that liberate kinetic energy for the particle ejection in sputtering are characteristic of the specific gas. (au) 3 tabs., 12 ills., 159 refs

  13. Metallic vapor supplying by the electron bombardment for a metallic ion production with an ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kitagawa, Atsushi; Sasaki, Makoto; Muramatsu, Masayuki [National Inst. of Radiological Sciences, Chiba (Japan); Jincho, Kaoru; Sasaki, Noriyuki; Sakuma, Tetsuya; Takasugi, Wataru; Yamamoto, Mitsugu [Accelerator Engineering Corporation, Chiba (Japan)

    2001-11-19

    To produce the metallic ion beam for the injection into the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), a new gas supply method has been developed for an 18 GHz ECR ion source (NIRS-HEC). A metallic target rod at a high positive potential is melted by the electron bombardment technique. The evaporated gas with a maximum flow rate of 50A/sec is supplied into the ECR plasma in case of Fe metal. (author)

  14. Metallic vapor supplying by the electron bombardment for a metallic ion production with an ECR ion source

    International Nuclear Information System (INIS)

    Kitagawa, Atsushi; Sasaki, Makoto; Muramatsu, Masayuki; Jincho, Kaoru; Sasaki, Noriyuki; Sakuma, Tetsuya; Takasugi, Wataru; Yamamoto, Mitsugu

    2001-01-01

    To produce the metallic ion beam for the injection into the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), a new gas supply method has been developed for an 18 GHz ECR ion source (NIRS-HEC). A metallic target rod at a high positive potential is melted by the electron bombardment technique. The evaporated gas with a maximum flow rate of 50A/sec is supplied into the ECR plasma in case of Fe metal. (author)

  15. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    Science.gov (United States)

    Cernusca, S.; Winter, HP.; Aumayr, F.; Díez Muiño, R.; Juaristi, J. I.

    2003-04-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to "projectile molecular effects" (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials.

  16. Production of Mg and Al Auger electrons by noble gas ion bombardment of Mg and Al surfaces. [3 KeV, electron promotion

    Energy Technology Data Exchange (ETDEWEB)

    Ferrante, J; Pepper, S V [National Aeronautics and Space Administration, Cleveland, Ohio (USA). Lewis Research Center

    1976-08-01

    In this letter the relative production efficiency of Mg and Al Auger electrons by He, Ne, Ar, Kr and Xe ion bombardment as a function of ion energy (<=3 keV) is reported. Some comments on the interpretation of the results in terms of electron promotion are also given.

  17. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    International Nuclear Information System (INIS)

    Cernusca, S.; Winter, H.P.; Aumayr, F.; Diez Muino, R.; Juaristi, J.I.

    2003-01-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy <10 keV) on atomically clean surfaces of carbon-fiber inforced graphite used as first-wall armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to 'projectile molecular effects' (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials

  18. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    CERN Document Server

    Cernusca, S; Aumayr, F; Diez-Muino, R; Juaristi, J I

    2003-01-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy <10 keV) on atomically clean surfaces of carbon-fiber inforced graphite used as first-wall armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to 'projectile molecular effects' (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials.

  19. Successive ionization of positive ions of carbon and nitrogen by electron bombardment

    International Nuclear Information System (INIS)

    Donets, E.D.; Ilyushchenko, V.I.

    Experimental studies of deep ionization of heavy ions are described. The applications of such studies in atomic physics, plasma physics and space physics are discussed. Investigations using intersecting ion-electron beams, shifted beams and ion trap sources are described, and data are presented for multi-charged ions of carbon, oxygen and nitrogen. A detailed description of the development of the IEL (electron beam ionizer) source, and the KRION (cryogenic version) source is given, and further data for the multiple ionization of carbon and nitrogen are given for charge states up to C 6+ and N 7+ . The advantages and disadvantages of the KRION source are discussed, and preliminary studies of a new torroidal ion trap source (HIRAC) are presented. (11 figs, 57 refs) (U.S.)

  20. Ion bombardment modification of surfaces

    International Nuclear Information System (INIS)

    Auciello, O.

    1984-01-01

    Ion bombardment-induced modification of surfaces may be considered one of the significant scientific and technological developments of the last two decades. The understanding acquired concerning the underlying mechanisms of several phenomena occurring during ion-surface interactions has led to applications within different modern technologies. These include microelectronics, surface acoustical and optical technologies, solar energy conversion, thin film technology, ion implantation metallurgy, nuclear track technology, thermonuclear fusion, vacuum technology, cold welding technology, biomedicine (implantology). It has become clear that information on many relevant advances, regarding ion bombardment modification of surfaces is dispersed among journals involving fields sometimes not clearly related. This may result, in some cases, in a loss of the type of interdisciplinary exchange of ideas, which has proved to be so fruitful for the advancement of science and technology. This book has been planned in an attempt to collect at least some of today's relevant information about the experimental and theoretical knowledge related to surface modification and its application to technology. (Auth.)

  1. Defect production and annihilation in metals through electronic excitation by energetic heavy ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Iwase, Akihiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Defect production, radiation annealing and defect recovery are studied in Ni and Cu irradiated with low-energy ({approx}1-MeV) and high-energy ({approx}100-MeV) ions. Irradiation of Ni with {approx}100-MeV ions causes an anomalous reduction, or even a complete disappearance of the stage-I recovery. This result shows that the energy transferred from excited electrons to lattice atoms through the electron-lattice interaction contributes to the annihilation of the stage-I interstitials. This effect is also observed in Ni as a large radiation annealing during 100-MeV heavy ion irradiation. On the other hand, in Cu thin foils, we find the defect production process strongly associated with electron excitation, where the defect production cross section is nearly proportional to S{sub e}{sup 2}. (author)

  2. Nucleation of diamond by pure carbon ion bombardment--a transmission electron microscopy study

    International Nuclear Information System (INIS)

    Yao, Y.; Liao, M.Y.; Wang, Z.G.; Lifshitz, Y.; Lee, S.

    2005-01-01

    A cross-sectional high-resolution transmission electron microscopy (HRTEM) study of a film deposited by a 1 keV mass-selected carbon ion beam onto silicon held at 800 deg. C is presented. Initially, a graphitic film with its basal planes perpendicular to the substrate is evolving. The precipitation of nanodiamond crystallites in upper layers is confirmed by HRTEM, selected area electron diffraction, and electron energy loss spectroscopy. The nucleation of diamond on graphitic edges as predicted by Lambrecht et al. [W. R. L. Lambrecht, C. H. Lee, B. Segall, J. C. Angus, Z. Li, and M. Sunkara, Nature, 364 607 (1993)] is experimentally confirmed. The results are discussed in terms of our recent subplantation-based diamond nucleation model

  3. Characterization techniques for ion bombarded insulators

    International Nuclear Information System (INIS)

    Borders, J.A.

    1987-01-01

    The chapter gives a comprehensive review of the experimental methods for the analysis of ion-bombarded insulators including optical and structural methods, resonance, energetic ion methods, and surface techniques. 48 refs.; 34 figs

  4. Origin of Si(LMM) Auger Electron Emission from Silicon and Si-Alloys by keV Ar+ Ion Bombardment

    Science.gov (United States)

    Iwami, Motohiro; Kim, Su Chol; Kataoka, Yoshihide; Imura, Takeshi; Hiraki, Akio; Fujimoto, Fuminori

    1980-09-01

    Si(LMM) Auger electrons emitted from specimens of pure silicon and several Si-alloys (Ni-Si, Pd-Si and Cu-Si) under keV Ar+ ion bombardment, were examined. In the Auger spectra from all specimens studied there were four peaks at energies of 92, 86, 76 and 66 eV. The Auger signal intensity varied considerably with both the incident angle and the energy of the primary ion beam. It is proposed that the Auger electrons are emitted from silicon atoms (or ions) just beneath the specimen surface but free from the bulk network.

  5. Origin of Si(LMM) Auger electron emission from silicon and Si-alloys by keV Ar/sup +/ ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Iwami, M; Kim, S; Kataoka, Y; Imura, T; Hiraki, A [Osaka Univ., Suita (Japan). Faculty of Engineering

    1980-09-01

    Si(LMM) Auger electrons emitted from specimens of pure silicon and several Si-alloys (Ni-Si, Pd-Si and Cu-Si) under keV Ar/sup +/ ion bombardment, were examined. In the Auger spectra from all specimens studied there were four peaks at energies of 92, 86, 76 and 66 eV. The Auger signal intensity varied considerably with both the incident angle and the energy of the primary ion beam. It is proposed that the Auger electrons are emitted from silicon atoms (or ions) just beneath the specimen surface but free from the bulk network.

  6. Anomalous microstructural changes in III-nitrides under ion bombardment

    International Nuclear Information System (INIS)

    Kucheyev, S.O.; Williams, J.S.; Jagadish, C.

    2002-01-01

    Full text: Group-III nitrides (GaN, AlGaN, and InGaN) are currently a 'hot topic' in the physics and material research community due to very important technological applications of these materials in (opto)electronics. In the fabrication of III-nitride-based devices, ion bombardment represents a very attractive processing tool. However, ion-beam-produced lattice disorder and its undesirable consequences limit technological applications of ion implantation. Hence, studies of ion-beam-damage processes in Ill-nitrides are not only physically interesting but also technologically important. In this study, wurtzite GaN, AlGaN, and InGaN films exposed to ion bombardment under a wide range of irradiation conditions are studied by a combination of transmission electron microscopy (TEM), environmental scanning electron microscopy (ESEM), energy dispersive x-ray spectrometry (EDS), atomic force microscopy (AFM), cathodoluminescence (CL), and Rutherford backscattering/channeling (RBS/C) spectrometry. Results show that, unlike the situation for mature semiconductors such as Si and GaAs, Ill-nitrides exhibit a range of intriguing behavior involving extreme microstructural changes under ion bombardment. In this presentation, the following aspects are discussed: (i) formation of lattice defects during ion bombardment, (ii) ion-beam-induced phase transformations, (iii) ion-beam-produced stoichiometric imbalance and associated material decomposition, and (iv) an application of charging phenomena during ESEM imaging for studies of electrical isolation in GaN by MeV light ion irradiation. Emphasis is given to the (powerful) application of electron microscopy techniques for the understanding of physical processes occurring in Ill-nitrides under ion bombardment. Copyright (2002) Australian Society for Electron Microscopy Inc

  7. Direct evidence for a thermal effect of Ar+ ion bombardment in a conventional sputtering mode

    International Nuclear Information System (INIS)

    Okuyama, F.; Fujimoto, Y.

    1986-01-01

    Evidence is presented that the Ar + ion bombardment for sputtering in Auger electron spectroscopy can heat the target up to 2000 0 C if the target has poor heat conduction. Polycrystalline microneedles of Cr exhibited spherical tips after being exposed to 3 keV Ar + ions, proving that the needle tips were melted by impacting Ar + ions. Microneedles of Mo ion bombarded under the same condition were bent plastically, which perhaps reflects the thermal annealing of the needles during ion bombardment

  8. Changes of electronic properties of p-GaN(0 0 0 1) surface after low-energy N+-ion bombardment

    Science.gov (United States)

    Grodzicki, M.; Mazur, P.; Ciszewski, A.

    2018-05-01

    The p-GaN(0 0 0 1) crystal with a relatively low acceptor concentration of 5 × 1016 cm-3 is used in these studies, which are carried out in situ under ultrahigh vacuum (UHV) by ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED). The p-GaN(0 0 0 1)-(1 × 1) surface is achieved by thermal cleaning. N+-ion bombardment by a 200 eV ion beam changes the surface stoichiometry, enriches it with nitrogen, and disorders it. Such modified surface layer inverts its semiconducting character from p- into n-type. The electron affinity for the already cleaned p-GaN surface and that just after bombardment shows a shift from 2.2 eV to 3.2 eV, as well as an increase of band bending at the vacuum/surface interface from 1.4 eV to 2.5 eV. Proper post-bombardment heating of the sample restores the initial atomic order of the modified layer, leaving its n-type semiconducting character unchanged. The results of the measurements are discussed based on two types of surface states concepts.

  9. Ion bombardment and disorder in amorphous silicon

    International Nuclear Information System (INIS)

    Sidhu, L.S.; Gaspari, F.; Zukotynski, S.

    1997-01-01

    The effect of ion bombardment during growth on the structural and optical properties of amorphous silicon are presented. Two series of films were deposited under electrically grounded and positively biased substrate conditions. The biased samples displayed lower growth rates and increased hydrogen content relative to grounded counterparts. The film structure was examined using Raman spectroscopy. The transverse optic like phonon band position was used as a parameter to characterize network order. Biased samples displayed an increased order of the amorphous network relative to grounded samples. Furthermore, biased samples exhibited a larger optical gap. These results are correlated and attributed to reduced ion bombardment effects

  10. Adhesion of evaporated titanium films to ion-bombarded polyethylene

    International Nuclear Information System (INIS)

    Bodoe, P.; Sundgren, J.

    1986-01-01

    Ti films were deposited onto high-density polyethylene (HDPE) samples by electron-beam evaporation. Prior to film deposition the samples were in situ pretreated by Ar ion bombardment using a sputter ion gun. The adhesion of the films, determined as the pull strength required for film failure, was measured as a function of ion dose. HDPE substrates processed at two different temperatures were examined. The adhesion of the Ti films to HDPE samples processed at roughly-equal150 0 C increased with the ion dose to a steady-state value corresponding to the cohesive strength of the HDPE substrate. The adhesion to the samples processed at roughly-equal200 0 C increased to a maximum and then decreased for further ion bombardment to a level of the same order as that for films deposited onto as-prepared samples. The effects of the ion bombardment upon the HDPE surface chemistry were examined by means of x-ray photoelectron spectroscopy (XPS). The ion bombardment resulted in dehydrogenation and cross linking of the surface region and for prolonged ion bombardment, a graphitelike surface was obtained. The film/substrate interface as well as the initial Ti film growth were examined by XPS analysis. A chemical interaction which resulted in Ti--C bonds was observed at the interface. The Ti film growth followed a pronounced three-dimensional growth mode on as-prepared surfaces whereas the ion bombardment resulted in a change toward a more two-dimensional growth mode. The difference in adhesion behavior for the two types of HDPE substrates was found to be due to a difference in the amounts of low molecular weight products present within the substrates

  11. Emission of positive oxygen ions from ion bombardment of adsorbate-covered metal surfaces

    International Nuclear Information System (INIS)

    Kaurin, M.G.

    1989-01-01

    During ion bombardment of metal surfaces, collision cascades can result in the emission of sputtered secondary ions. Recent experiments, however, have suggested that the emission of positive ions of electronegative adsorbates can result from electronic processes rather than from processes involving elastic collisions. This dissertation presents the results of experiments studying the emission of positive oxygen ions from oxygen- and carbon-monoxide-covered transition metal surfaces during bombardment by 25-250 keV ions of neon, argon, and krypton. The systems studied may be grouped into four categories. For a nickel substrate with adsorbed oxygen, the emission of positive oxygen ions proceeds through collision cascades. For titanium and niobium with adsorbed oxygen, the emission of positive oxygen ions is proportional to the primary ion velocity, consistent with emission from electronic processes; for a given primary ion velocity, the oxygen ion yield is independent of primary ion species. For substrates of molybdenum and tungsten, the oxygen yield is proportional to primary ion velocity, but the yield also depends on the primary ion species for a given primary ion velocity in a manner that is consistent with emission resulting from electronic processes. For these two groups, except for titanium, the yields during neon ion bombardment do not extrapolate (assuming linearity with primary ion velocity) to a nonzero value at zero beam velocity. The magnitude of the oxygen ion yields from these targets is not consistent with that expected if the emission were induced by secondary electrons emitted during the ion bombardment

  12. Compositional changes during ion bombardment

    International Nuclear Information System (INIS)

    Rehn, L.E.

    1988-09-01

    Ion irradiation initiates several processes that can alter the composition of the target. This presentation provides an overview of our current understanding of these kinetics processes, which include implantation, sputtering, displacement mixing, radiation-enhanced diffusion, and radiation-induced segregation. The latter two effects can alter the target composition to depths that are substantially greater than the projected ion range. 45 refs., 8 figs

  13. Magnetoresistance and ion bombardment induced magnetic patterning

    International Nuclear Information System (INIS)

    Hoeink, V.

    2008-01-01

    In this thesis the combination of the magnetic patterning of the unidirectional anisotropy and the tunnel magnetoresistance effect is investigated. In my diploma thesis, it has been shown that it is in principle possible to use the magnetic patterning by ion bombardment to magnetically structure the pinned layer in magnetic tunnel junctions (MTJs) with alumina barrier. Furthermore, it has been shown that the side effects which have been observed after this treatment can be at least reduced by an additional heating step. Starting from this point, the applicability of ion bombardment induced magnetic patterning (IBMP) in general and the combination of IBMP and MTJs in particular is investigated and new applications are developed. (orig.)

  14. Ion bombardment techniques - recent developments in SIMS

    International Nuclear Information System (INIS)

    Konarski, P.; Miśnik, M.

    2013-01-01

    We present a short review of cluster ion bombardment technique recently applied in SIMS. Many advantages of using cluster ion beams are specified over monoatomic ion species. Cluster ions open really new perspectives especially in organic based structures analysis. Nevertheless cluster ions are not the perfect solution and still new ideas of ion erosion in SIMS are needed. Another issue discussed is 'storing matter' technique applied for quantitative analysis in SIMS. Simple idea of sputter deposition of eroded material onto rotating substrate and then analysing the stored material allows to avoid strong matrix effects in SIMS. Presented are the results performed in Tele and Radio Research Institute, Warszawa, Poland. These are the first results of ‘storing matter’ technique performed in one analytical chamber of SIMS instrument. (authors)

  15. Studies on the bombardment of condensed molecular gases at liquid-He temperatures by keV electrons and light ions

    International Nuclear Information System (INIS)

    Boergesen, P.

    1982-09-01

    Films of solid H 2 , D 2 and N 2 were irradiated with keV electrons and ions. Stopping cross sections and ranges of 0.3-10 keV/amu light ions in solid H 2 and D 2 are in good agreement with experimental and theoretical data on gaseous targets. In contrast, both stopping cross section and range measurements in solid N 2 suggest that the stopping here is only about half of that in N 2 -gas. This ''phase-effect'' is further supported by secondary emission measurements. Secondary electron emission coefficients for 2-10 keV H 1 + , H 2 + , H 3 + , D 3 + , D 2 H + , 4 He + , 14 N + and 20 Ne + incident on solids H 2 , D 2 and N 2 are in reasonable agreement with previous results for electron-incidence. The rather large erosion yields for 1-3 keV electrons incident on solid D 2 depend strongly on target thickness (for thin films), but weakly on energy. Bulk yields for 2 keV electrons were approximately 8 H 2 /electron, approximately 4 D 2 /electron and approximately 0.5 N 2 /electron. Secondary ion emission during ion bombardment seems to be predominantly reflected projectiles in the case of N 2 -targets, while it may be explained as sputtered particles from H 2 - and D 2 -targets. Preliminary results on the erosion of solid H 2 and D 2 by keV light ions indicate very large erosion yields (approx. 400 H 2 /atom for 2 keV protons) increasing strongly with energy. (Auth.)

  16. Adhesion of silver films to ion-bombarded alumina

    International Nuclear Information System (INIS)

    Erck, R.A.; Fenske, G.R.

    1990-01-01

    This paper reports on silver films deposited on alumina substrates using ion bombardment. Adhesion strength was measured as a function of deposition conditions, sputter-cleaning time, and bombarding ion species, using a pull-type adhesion tester. Argon- and argon/oxygen-ion sputtering produced large increases in adhesion strength, with the greatest increases occurring for oxygen-ion bombardment. Adhesion strength increased monotonically as a function of ion sputtering time. At a given deposition rate, further enhancement of adhesion is seen with concurrent ion bombardment

  17. Modification of thin film properties by ion bombardment during deposition

    International Nuclear Information System (INIS)

    Harper, J.M.E.; Cuomo, J.J.; Gambino, R.J.; Kaufman, H.R.

    1984-01-01

    Deposition methods involving ion bombardment are described, and the basic processes with which film properties are modified by ion bombardment are summarized. Examples of thin film property modification by ion bombardment during deposition, including effects which are primarily compositional as well as those which are primarily structural are presented. The examples demonstrate the usefulness of ion beam techniques in identifying and controlling the fundamental deposition parameters. 68 refs.; 15 figs.; 1 table

  18. Miniature electron bombardment evaporation source: evaporation rate measurement

    International Nuclear Information System (INIS)

    Nehasil, V.; Masek, K.; Matolin, V.; Moreau, O.

    1997-01-01

    Miniature electron beam evaporation sources which operate on the principle of vaporization of source material, in the form of a tip, by electron bombardment are produced by several companies specialized in UHV equipment. These sources are used primarily for materials that are normally difficult to deposit due to their high evaporation temperature. They are appropriate for special applications such as heteroepitaxial thin film growth requiring a very low and well controlled deposition rate. A simple and easily applicable method of evaporation rate control is proposed. The method is based on the measurement of ion current produced by electron bombardment of evaporated atoms. The absolute evaporation flux values were measured by means of the Bayard-Alpert ion gauge, which enabled the ion current vs evaporation flux calibration curves to be plotted. (author). 1 tab., 4 figs., 6 refs

  19. Modification of thin film properties by ion bombardment during deposition

    International Nuclear Information System (INIS)

    Harper, J.M.E.; Cuomo, J.J.; Gambino, R.J.; Kaufman, H.R.

    1984-01-01

    Many thin film deposition techniques involve some form of energetic particle bombardment of the growing film. The degree of bombardment greatly influences the film composition, structure and other properties. While in some techniques the degree of bombardment is secondary to the original process design, in recent years more deposition systems are being designed with the capability for controlled ion bombardment of thin films during deposition. The highest degree of control is obtained with ion beam sources which operate independently of the vapor source providing the thin film material. Other plasma techniques offer varying degrees of control of energetic particle bombardment. Deposition methods involving ion bombardment are described, and the basic processes with which film properties are modified by ion bombardment are summarized. (Auth.)

  20. Experiments on secondary ion emission with multicharged keV ion bombardement

    International Nuclear Information System (INIS)

    Della Negra, S.; Depauw, J.; Joret, H.; Le Beyec, Y.; Schweikert, E.A.

    1987-01-01

    An electron cyclotron resonance ion source was used to study the influence of the incident charge state of keV ions on secondary ion emission. The experiments were run with 18 keV Arn+ (1 < n < 11) beams produced by a minimafios source. Various types of targets were bombarded by the ion beam and the sputtered ionized species were identified by time of flight mass spectrometry. The experimental arrangement is detailed and preliminary results are indicated

  1. Cesium ion bombardment of metal surfaces

    International Nuclear Information System (INIS)

    Tompa, G.S.

    1986-01-01

    The steady state cesium coverage due to cesium ion bombardment of molybdenum and tungsten was studied for the incident energy range below 500 eV. When a sample is exposed to a positive ion beam, the work function decreases until steady state is reached with a total dose of less than ≅10 16 ions/cm 2 , for both tungsten and molybdenum. A steady state minimum work function surface is produced at an incident energy of ≅100 eV for molybdenum and at an incident energy of ≅45 eV for tungsten. Increasing the incident energy results in an increase in the work function corresponding to a decrease in the surface coverage of cesium. At incident energies less than that giving the minimum work function, the work function approaches that of cesium metal. At a given bombarding energy the cesium coverage of tungsten is uniformly less than that of molybdenum. Effects of hydrogen gas coadsorption were also examined. Hydrogen coadsorption does not have a large effect on the steady state work functions. The largest shifts in the work function due to the coadsorption of hydrogen occur on the samples when there is no cesium present. A theory describing the steady-state coverage was developed is used to make predictions for other materials. A simple sticking and sputtering relationship, not including implantation, cannot account for the steady state coverage. At low concentrations, cesium coverage of a target is proportional to the ratio of (1 - β)/γ where β is the reflection coefficient and γ is the sputter yield. High coverages are produced on molybdenum due to implantation and low backscattering, because molybdenum is lighter than cesium. For tungsten the high backscattering and low implantation result in low coverages

  2. Cleaning of diffusion bonding surface by argon ion bombardment treatment

    International Nuclear Information System (INIS)

    Wang, Airu; Ohashi, Osamu; Yamaguchi, Norio; Aoki, Masanori; Higashi, Yasuo; Hitomi, Nobuteru

    2003-01-01

    The specimens of oxygen-free high conductivity copper, SUS304L stainless steel and pure iron were treated by argon ion bombardment and then were bonded by diffusion bonding method. The effects of argon ion bombardment treatment on faying surface morphology, tensile strength of bonding joints and inclusions at the fracture surface were investigated. The results showed that argon ion bombardment treatment was effective to remove the oxide film and contamination at the faying surface and improve the quality of joints. The tensile strength of the bonded joints was improved, and minimum bonding temperature to make the metallic bonding at the interface was lowered by argon ion bombardment treatment. At the joints with argon ion bombardment treatment, ductile fractured surface was seen and the amount of inclusions was obviously decreased

  3. Impact of Ion Bombardment on the Structure and Magnetic Properties of Fe78Si13B9 Amorphous Alloy

    Science.gov (United States)

    Wu, Yingwei; Peng, Kun

    2018-06-01

    Amorphous Fe78Si13B9 alloy ribbons were bombarded by ion beams with different incident angles ( θ ). The evolution of the microstructure and magnetic properties of ribbons caused by ion beam bombardment was investigated by x-ray diffraction, transmission electron microscope and vibrating sample magnetometer analysis. Low-incident-angle bombardment led to atomic migration in the short range, and high-incident-angle bombardment resulted in the crystallization of amorphous alloys. Ion bombardment induces magnetic anisotropy and affects magnetic properties. The effective magnetic anisotropy was determined by applying the law of approach to saturation, and it increased with the increase of the ion bombardment angle. The introduction of effective magnetic anisotropy will reduce the permeability and increase the relaxation frequency. Excellent high-frequency magnetic properties can be obtained by selecting suitable ion bombardment parameters.

  4. Preliminary report into the effects of nitrogen ion bombardment treatment on mustard seeds

    International Nuclear Information System (INIS)

    Smith, C.W.; Al-Hashmi, S.A.R.; Ahmed, N.A.G.; Pollard, M.

    1988-01-01

    Mustard seeds have been subjected to nitrogen ion bombardment. A range of conditions was found within which there was an enhancement in the growth of seedlings from the ion bombardment treated seeds relative to those grown from control seeds. Scanning electron microscopy was used to examine seeds after treatment. It appeared that there had been an etching of the seed coating by the ion bombardment. This view was supported by experiments which showed that the rate of capillary water uptake by the treated seeds had been enhanced. (author)

  5. Modification of Polymer Materials by Ion Bombardment: Case Studies

    International Nuclear Information System (INIS)

    Bielinski, D. M.; Jagielski, J.; Lipinski, P.; Pieczynska, D.; Ostaszewska, U.; Piatkowska, A.

    2009-01-01

    The paper discusses possibility of application of ion beam bombardment for modification of polymers. Changes to composition, structure and morphology of the surface layer produced by the treatment and their influence on engineering and functional properties of wide range of polymer materials are presented. Special attention has been devoted to modification of tribological properties. Ion bombardment results in significant reduction of friction, which can be explained by increase of hardness and wettability of polymer materials. Hard but thin enough skin does not result in cracking but improves their abrasion resistance. Contrary to conventional chemical treatment ion beam bombardment works even for polymers hardly susceptible to modification like silicone rubber or polyolefines.

  6. Continuum radiation emitted from transition metals under ion bombardment

    International Nuclear Information System (INIS)

    El Boujlaidi, A.; Kaddouri, A.; Ait El Fqih, M.; Hammoum, K.; Aouchiche, H.

    2012-01-01

    Optical emission of transition metals has been studied during 5 keV Kr + ions bombardment within and without oxygen atmosphere in the colliding chamber. The observed spectra consist of a series of discrete lines superimposed on a broad continuum. Generally, the emission intensity was influenced by the presence of oxygen giving rise to transient effects as well as to an increase in the line intensity. The behaviours of spectral lines were successfully explained in term of electron-transfer process between the excited sputtered atom and the solid surface. In this work, we have focused our study on the continuous radiation emitted during ion bombardment. The experimental results suggest that the continuum emission depends on the nature of metal and very probably related to its electronic structure. The collective deactivation of 3d-shell electrons appears to play a role in the emission of this radiation. The observed enhancement in the presence of oxygen is probably due to a significant contribution of the oxide molecules. (authors)

  7. Study on evolution of gases from fluoropolymer films bombarded with heavy ions

    International Nuclear Information System (INIS)

    Minamisawa, Renato Amaral; Zimmerman, Robert Lee; Budak, Satilmis; Ila, Daryush

    2008-01-01

    Ion beam bombardment provides a unique way of material modification by inducing a high degree of localized electronic excitation. The ion track, or affected volume along the ion path through the material is related to the total damage and possible structural changes. Here we study the evolution of gases emitted by poly(tetrafluorethylene-co-perfluoro-(propyl vinyl ether)) (PFA) fluoropolymer bombarded with MeV gold ions. The gas was monitored by a residual gas analyzer (RGA), as a function of the ion fluence. Micro-Raman, atomic force microscopy and optical absorption were used to analyze the chemical structure changes and sputtering yield

  8. Computer simulation of the topography evolution on ion bombarded surfaces

    CERN Document Server

    Zier, M

    2003-01-01

    The development of roughness on ion bombarded surfaces (facets, ripples) on single crystalline and amorphous homogeneous solids plays an important role for example in depth profiling techniques. To verify a faceting mechanism based not only on sputtering by directly impinging ions but also on the contribution of reflected ions and the redeposition of sputtered material a computer simulation has been carried out. The surface in this model is treated as a two-dimensional line segment profile. The model describes the topography evolution on ion bombarded surfaces including the growth mechanism of a facetted surface, using only the interplay of reflected and primary ions and redeposited atoms.

  9. InN: Fermi level stabilization by low-energy ion bombardment

    International Nuclear Information System (INIS)

    Piper, L.F.J.; Veal, T.D.; McConville, C.F.; Lu, H.; Schaff, W.J.

    2006-01-01

    The near-surface electronic properties of InN have been investigated with high-resolution electron-energy loss spectroscopy. Low-energy (∝400 eV) nitrogen ion bombardment followed by low temperature annealing (<300 C) was found to dramatically increase the n-type conductivity of InN, close to the surface. This is explained in terms of the formation of amphoteric defects from the ion bombardment and annealing combined with the band structure of InN. Low-energy ion bombardment and annealing is shown to result in a damage-induced, donor-like defect-profile instead of the expected electron accumulation for InN. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Annealing of defects in indium antimonide after ion bombardment

    International Nuclear Information System (INIS)

    Bogatyrev, V.A.; Kachurin, G.A.

    1977-01-01

    Indium antimonide electric properties are investigated after ion bombardment of different mass (with energy of 60 and 300 keV) and isochrone annealing in the 20-450 deg C temperature range. It is shown that 100-150 deg C n- type stable layers are formed after proton irradiation at room temperature only. Indium antimonide exposure by average mass ions under the same conditions and also by helium ions of 300 keV energy brings to p-type layer formation with high hole concentration. Subsequent heating at the temperature over 150 deg C results in electron conductivity of irradiated layers. Electron volume density and mobility efficiency reaches 10 18 cm -3 and 10 4 cm 2 /Vs respectively. N-type formed layers are stable up to 350 deg C allowing its usage for n-p transition formation admitting thermal treatment. Analysis is given of defect behaviour peculiarities depending upon the irradiation and annealing conditions. Hole conductivity in irradiated indium antimonide is supposed to be stipulated by regions of disorder, while electron conductivity - by relatively simpler disorders

  11. Ion plasma electron gun

    International Nuclear Information System (INIS)

    Wakalopulos, G.

    1976-01-01

    In the disclosed electron gun positive ions generated by a hollow cathode plasma discharge in a first chamber are accelerated through control and shield grids into a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode causing the cathode to emit secondary electrons which form an electron beam having a distribution adjacent to the cathode emissive surface substantially the same as the distribution of the ion beam impinging upon the cathode. After passing through the grids and the plasma discharge chamber, the electron beam exits from the electron gun via a foil window. Control of the generated electron beam is achieved by applying a relatively low control voltage between the control grid and the electron gun housing (which resides at ground potential) to control the density of the positive ions bombarding the cathode

  12. Effect of ion beam bombardment on the carbide in M2 steel modified by ion-beam-assisted deposition

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.Y.; Wang, F.J.; Wang, Y.K. (Dept. of Materials Engineering, Dalian Univ. of Technology (China)); Ma, T.C. (National Lab. of Materials Modification by Beam Three, Dalian (China))

    1991-10-30

    Transmission electron microscopy was used to study the effect of nitrogen ion bombardment with different doses on the carbides in M2 high speed steel as the nitrogen ions penetrated into the nitride films during ion-beam-assisted deposition. With different doses of nitrogen, alterations in the morphological characteristics of the carbide M6C at the interface were observed. With lower doses, knitting-like contrast within the carbide showed subboundary structure defects in M6C. With increasing dose, the substructure defects were broken up into small fragments owing to heavy bombardment. The microstructures of carbides at the interface damaged by nitrogen ions are discussed in detail. (orig.).

  13. Catalytic oxidation of silicon by cesium ion bombardment

    International Nuclear Information System (INIS)

    Souzis, A.E.; Huang, H.; Carr, W.E.; Seidl, M.

    1991-01-01

    Results for room-temperature oxidation of silicon using cesium ion bombardment and low oxygen exposure are presented. Bombardment with cesium ions is shown to allow oxidation at O 2 pressures orders of magnitude smaller than with noble gas ion bombardment. Oxide layers of up to 30 A in thickness are grown with beam energies ranging from 20--2000 eV, O 2 pressures from 10 -9 to 10 -6 Torr, and total O 2 exposures of 10 0 to 10 4 L. Results are shown to be consistent with models indicating that initial oxidation of silicon is via dissociative chemisorption of O 2 , and that the low work function of the cesium- and oxygen-coated silicon plays the primary role in promoting the oxidation process

  14. Ion bombardment induced ripple topography on amorphous solids

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.; Paton, F.; Williams, J.S.

    1977-01-01

    Earlier studies of the ion bombardment induced ripple morphology on the surfaces of amorphous solids when compared with geomorphological effects are shown to possess many similar features. The present study, with 40 keV Ar + ion bombarded Si suggests that analogies are incomplete, however, and that greater similarities with the process of macroscopic sandblasting (corrosion) exist. It is shown that the genesis of wave like structures on Si is from isolated features, which have the appearance of ripple trains, which are faceted. It is suggested that these features result from particle flux enhancement processes near surface dimples generated by stress induced surface lifting. (author)

  15. Si(LMM) Auger electron emission from Si alloys by keV Ar/sup +/ ion bombardment, new effect and application

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, A; Kim, S; Imura, T; Iwami, M [Osaka Univ., Suita (Japan). Faculty of Engineering

    1979-09-01

    Si(LMM) Auger spectra excited by keV ion bombardment were studied in Si alloyed with several elements (Au, Cu, Pd, Ni, C, and H). The spectra differed completely from those of pure Si. The main characteristics are (1) the spectra are composed of two well-separated peaks (88 and 92 eV) called the atomic-like peak (88 eV) and the bulk-like peak (92 eV); and (2) the atomic-like peak is enhanced with respect to the bulk-like peak, and this enhancement becomes more obvious as the concentration of partner elements of the alloys are increased. The possible application of the present phenomena is proposed as a technique for detecting the homogeneity of Si alloy films in the three-dimensional sense - as an example, the three-dimensional distribution of hydrogen in hydrogenated amorphous silicon (a-Si-H).

  16. Ion bombardment induced surface topography modification of clean and contaminated single crystal Cu and Si

    International Nuclear Information System (INIS)

    Lewis, G.W.; Kiriakides, G.; Carter, G.; Nobes, M.J.

    1982-01-01

    Among the several factors which lead to depth resolution deterioration during sputter profiling, surface morphological modification resulting from local differences of sputtering rate can be important. This paper reports the results of direct scanning, electron microscopic studies obtained quasi-dynamically during increasing fluence ion bombardment of the evolution of etch pit structures on Si and Cu, and how such elaboration may be suppressed. It also reports on the elaboration of contaminant-induced cone generation for different ion species bombardment. The influence of such etch pit and cone generation on achievable depth resolution is assessed. (author)

  17. The influence of ion bombardment on emission properties of carbon materials

    International Nuclear Information System (INIS)

    Chepusov, Alexander; Komarskiy, Alexander; Kuznetsov, Vadim

    2014-01-01

    When electric-vacuum device works its cathode surface experiences bombardment with ions of residual gases. Effects of ion bombardment impact on surface of field emission cathodes made of carbon materials may essentially change emission properties of such cathodes. It changes emission start electric field strength, voltage vs. current characteristic of material, its relief and electron structure of the surface layer. Field emission cathode operating mode, variation of radiation doses allow to obtain both good effects: maximal electric current, surface recovery – and negative ones: the worst emission properties and surface destruction, amorphization.

  18. The influence of ion bombardment on emission properties of carbon materials

    Energy Technology Data Exchange (ETDEWEB)

    Chepusov, Alexander, E-mail: chepusov@iep.uran.ru [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation); Ural Federal University, 620002, 19 Mira Street, Ekaterinburg (Russian Federation); Komarskiy, Alexander, E-mail: aakomarskiy@gmail.com [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation); Ural Federal University, 620002, 19 Mira Street, Ekaterinburg (Russian Federation); Kuznetsov, Vadim, E-mail: kuznetsov@iep.uran.ru [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation)

    2014-07-01

    When electric-vacuum device works its cathode surface experiences bombardment with ions of residual gases. Effects of ion bombardment impact on surface of field emission cathodes made of carbon materials may essentially change emission properties of such cathodes. It changes emission start electric field strength, voltage vs. current characteristic of material, its relief and electron structure of the surface layer. Field emission cathode operating mode, variation of radiation doses allow to obtain both good effects: maximal electric current, surface recovery – and negative ones: the worst emission properties and surface destruction, amorphization.

  19. The surface topography of Inconel, stainless steel and copper after argon ion bombardment

    International Nuclear Information System (INIS)

    Vogelbruch, K.; Vietzke, E.

    1983-01-01

    Energetic particle bombardment of metals is known to change the surface topography. To simulate the behaviour of the first wall of a fusion device under real plasma conditions, we have investigated the surface topography of rotating targets after 30 keV argon ion bombardment at 70deg incident angle by electron scanning micrographs. Under these conditions Inconel 600, 601, 625, stainless steel, and copper showed no cones, pyramids or cliffs, but only etching figures and at higher ion doses relatively flat hills. Thus, it can be concluded, that the influence of energetic particles on the first wall of a fusion reactor is smaller than expected from the results of such sputtering experiments, which have dealt with the formation of surface structures under ion bombardment at constant incident direction. (author)

  20. Effects of uranium bombardment by 20-40 KeV argon ions, Annex 2

    International Nuclear Information System (INIS)

    Nenadovic, T.; Jurela, Z.

    1966-01-01

    This paper shows the results of argon ions interaction with the polycrystal natural uranium. Thin foil of uranium about 200 μ was bombarded by 20-40 KeV argon ions. Coefficients of cathode scattering δ and secondary electrons emission γ were measured, during the process A + →U. The foil was then studied by transmission method and method of single step replica using an electron microscope [sr

  1. Ion bombardment effect on surface state of metal

    International Nuclear Information System (INIS)

    Vaulin, E.P.; Georgieva, N.E.; Martynenko, T.P.

    1990-01-01

    The effect of slow argon ion bombardment on the surface microstructure of polycrystalline copper as well as the effect of surface state on sputtering of D-16 polycrystalline alloy are experimentally studied. Reduction of copper surface roughness is observed. It is shown that the D-16 alloy sputtering coefficient is sensitive to the surface state within the limits of the destructed surface layer

  2. Ion bombardment simulation: a review related to fusion radiation damage

    International Nuclear Information System (INIS)

    Brimhall, J.L.

    1975-01-01

    Prime emphasis is given to reviewing the ion bombardment data on the refractory metals molybdenum, niobium and vanadium which have been proposed for use in advanced fusion devices. The temperature and dose dependence of the void parameters are correlated among these metals. The effect of helium and hydrogen gas on the void parameters is also included. The similarities and differences of the response of these materials to high dose, high temperature radiation damage are evaluated. Comparisons are made with results obtained from stainless steel and nickel base alloys. The ion bombardment data is then compared and correlated, as far as possible, with existing neutron data on the refractory metals. The theoretically calculated damage state produced by neutrons and ions is also briefly discussed and compared to experimental data wherever possible. The advantages and limitations of ion simulation in relation to fusion radiation damage are finally summarized

  3. Destruction of C60 films by boron ion bombardment

    International Nuclear Information System (INIS)

    Ren Zhongmin; Du Yuancheng; Ying Zhifeng; Xiong Xiaxing; Li Fuming

    1995-01-01

    C 60 films are bombarded by 100 keV boron ion beams at doses ranging from 3x10 14 to 1x10 16 /cm 2 . The bombarded films are analyzed using Fourier transform infrared spectroscopy (FTIR), Raman spectra and X-ray diffraction (XRD) measurements. Most C 60 soccer-balls in the implanted region in the films are found to be broken at a dose over 1x10 15 /cm 2 , while at a dose less than 6x10 14 /cm 2 a few C 60 molecules remain undestroyed and maintain some crystal structure. The results of the analyses suggest a complete disintegration of a C 60 molecule under B + bombardment. ((orig.))

  4. Auger emission from solid surfaces bombarded with ions

    International Nuclear Information System (INIS)

    Grizzi, Oscar.

    1986-01-01

    The Auger electron emission from Be, Na, Mg, Al and Si bombarded with 0,5-20 KeV noble gas ions is studied. Sharp structures of the Auger electron spectra of Na and Be were identified. A Monte Carlo program was adapted to simulate the colision cascade in the solid, inner shell excitations and Auger decays. From the comparision of experimental and simulated Auger intensities, the relative role of symmetric and asymmetric collisions in Be K- and Al L-shell excitation were evaluated. In the case of Be, the discussion of the exciting processes to higher projectile energies was extended. To this end, the simulation to early measurements of Be K X-ray yields was applied. From this analysis, information about the variations of the fluorescence yield and outer-shell occupation numbers of Be with projectile energy was obtained. The study of the shape of the sharp Auger structures and their dependence with the energy and incidence projectile angle gives information about the collisional processes, inner hole lifetimes and Auger decays. From the evaluation of the energy and angular distribution of the excited sputtered atoms and the interaction between them and the metallic-surface, the energy shift distributions in the Auger energies were obtained. From the comparison of these distributions with the experimental atomic peaks, the main causes of the broadening of these peaks were determined. (M.E.L.) [es

  5. Friction and wear measurements of sputtered MoS/sub x/ films amorphized by ion bombardment

    International Nuclear Information System (INIS)

    Mikkelsen, N.J.; Chevallier, J.; Soerensen, G.; Straede, C.A.

    1988-01-01

    The present study presents an experimental evidence for amorphization of rf sputtered MoS/sub x/ films by ion bombardment. Even at low doses (3 x 10 15 ions/cm 2 ) of 400 keV argon ions a complete amorphization was confirmed by x-ray diffraction analysis and transmission electron microscopy. As a result of the ion bombardment the film density increased 100% to almost the bulk value for MoS 2 . The friction coefficient for ion beam amorphized MoS/sub x/ was measured to be 0.04 in agreement with the values reported for crystalline films but disagreeing considerably with the friction coefficient of 0.4 previously reported for amorphous films

  6. Development of pits and cones on ion bombarded copper

    International Nuclear Information System (INIS)

    Tanovic, L.A.; Carter, G.; Nobes, M.J.; Whitton, I.L.; Williams, J.S.

    1980-01-01

    The formation of pits and cones on Ar ion bombarded copper has been studied. Carefully polished surfaces of large grained 99.999% pure copper crystals have been bombarded at normal incidence with 40 keV argon ions. The cone formation has been investigated for annealed and non-annealed crystals at room temperature and at 30 K and in the case of monocrystal and polycrystal samples. Although in the most other studies the presence of impurities is as a necessary condition for generation of cones and pits the obtained experimental results show that under certain conditions these features are formed on clean surfaces. It is shown that the dominant parameter in the production of cones on copper is the crystal orientation [ru

  7. Thermo-mechanical design aspects of mercury bombardment ion thrusters.

    Science.gov (United States)

    Schnelker, D. E.; Kami, S.

    1972-01-01

    The mechanical design criteria are presented as background considerations for solving problems associated with the thermomechanical design of mercury ion bombardment thrusters. Various analytical procedures are used to aid in the development of thruster subassemblies and components in the fields of heat transfer, vibration, and stress analysis. Examples of these techniques which provide computer solutions to predict and control stress levels encountered during launch and operation of thruster systems are discussed. Computer models of specific examples are presented.

  8. Investigation of the surface morphology of ion-bombarded biocompatible materials with a SEM and profilograph

    International Nuclear Information System (INIS)

    Kowalski, Z.W.

    1984-01-01

    The surface morphology (topography and roughness) is a very important factor which affects the response of biological tissue to an implant material. The effect of an incident ion beam on surface morphology of various biocompatible materials was studied. All materials were bombarded by Ar + ions at an applied voltage of 7 kV at various incident angles from 0 to 1.4 rad (0 to 80 deg) and at a beam current up to 0.1 mA. The surface topographies of ion-bombarded samples were examined with a Japan Electron Optics Laboratory, model JSM-35, scanning electron microscope. The roughness of the surface was calculated from the shape of a surface profile, which was recorded by a profilograph, the ME 10 (supplied by VEB Carl Zeiss, Jena). (author)

  9. The effect of incidence angle on ion bombardment induced surface topography development on single crystal copper

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.; Lewis, G.W.; Whitton, J.L.

    1982-01-01

    The fluence dependence of development of microscopic surface features, particularly etch pits, during 9 keV Ar + ion bombardment of (11,3,1) oriented Cu single crystals has been studied employing quasi-dynamic irradiation and observation techniques in a scanning electron microscope-accelerator system. 9 keV ions are observed not to produce crystallographic pyramids under all irradiation conditions for this surface, a very different result from our earlier studies with higher energy ions. The bombardment does elaborate etch pits however, the habits and growth kinetics of which depend upon both polar and azimuthal angles of ion incidence to the surface. The results are explained in terms of differential erosion of crystal planes modified by the presence of pre-existing and irradiation induces extended defects. (orig.)

  10. Anomalous heat evolution of deuteron implanted Al on electron bombardment

    International Nuclear Information System (INIS)

    Kamada, K.; Kinoshita, H.; Takahashi, H.

    1994-05-01

    Anomalous heat evolution was observed in deuteron implanted Al foils on 175 keV electron bombardment. Local regions with linear dimension of several 100nm showed simultaneous transformation from single crystalline to polycrystalline structure instantaneously on the electron bombardment, indicating the temperature rise up to more than melting point of Al from room temperature. The amount of energy evolved was more than 180 MeV for each transformed region. The transformation was never observed in proton implanted Al foils. The heat evolution was considered due to a nuclear reaction in D 2 molecular collections. (author)

  11. Ultra-low-energy (<10 eV/u) ion beam bombardment effect on naked DNA

    Energy Technology Data Exchange (ETDEWEB)

    Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2014-05-01

    Highlights: • Decelerated ultra-low energy ion beam bombarded naked DNA. • DNA form change induced by ion bombardment was investigated. • N-ion bombardment at 32 eV induced DNA single and double strand breaks. • Ar-ion bombardment at a-few-hundreds eV induced DNA single strand break. - Abstract: Since ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range, it is very interesting to know effects from ultra-low-energy ion interaction with DNA for understanding ion-beam-induced genetic mutation. Tens-keV Ar- and N-ion beams were decelerated to ultra-low energy ranging from 20 to 100 eV, or only a few to 10 eV/u, to bombard naked plasmid DNA. The bombarded DNA was analyzed using gel electrophoresis for DNA form changes. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks after bombarded by tens-eV ion beam. N-ion beam was found more effective in inducing DNA change and mutation than Ar-ion beam. The study demonstrated that the ion bombardment with energy as low as several-tens eV was able to break DNA strands and thus potentially to cause genetic modification of biological cells. The experimental results were discussed in terms of direct atomic collision between the ions and DNA atoms.

  12. Ultra-low-energy (<10 eV/u) ion beam bombardment effect on naked DNA

    International Nuclear Information System (INIS)

    Thopan, P.; Thongkumkoon, P.; Prakrajang, K.; Suwannakachorn, D.; Yu, L.D.

    2014-01-01

    Highlights: • Decelerated ultra-low energy ion beam bombarded naked DNA. • DNA form change induced by ion bombardment was investigated. • N-ion bombardment at 32 eV induced DNA single and double strand breaks. • Ar-ion bombardment at a-few-hundreds eV induced DNA single strand break. - Abstract: Since ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range, it is very interesting to know effects from ultra-low-energy ion interaction with DNA for understanding ion-beam-induced genetic mutation. Tens-keV Ar- and N-ion beams were decelerated to ultra-low energy ranging from 20 to 100 eV, or only a few to 10 eV/u, to bombard naked plasmid DNA. The bombarded DNA was analyzed using gel electrophoresis for DNA form changes. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks after bombarded by tens-eV ion beam. N-ion beam was found more effective in inducing DNA change and mutation than Ar-ion beam. The study demonstrated that the ion bombardment with energy as low as several-tens eV was able to break DNA strands and thus potentially to cause genetic modification of biological cells. The experimental results were discussed in terms of direct atomic collision between the ions and DNA atoms

  13. An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

    Energy Technology Data Exchange (ETDEWEB)

    Thopan, P.; Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuldyuld@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells.

  14. An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

    International Nuclear Information System (INIS)

    Thopan, P.; Prakrajang, K.; Thongkumkoon, P.; Suwannakachorn, D.; Yu, L.D.

    2013-01-01

    Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells

  15. Calculations on displacement damage and its related parameters for heavy ion bombardment in reactor materials

    International Nuclear Information System (INIS)

    Sone, Kazuho; Shiraishi, Kensuke

    1975-04-01

    The depth distribution of displacement damage expressed in displacements per atom (DPA) in reactor materials such as Mo, Nb, V, Fe and Ni bombarded by energetic nitrogen, argon and self ions with incident energy below 2 MeV was calculated following the theory developed by Lindhard and co-workers for the partition of energy as an energetic ion slowing down. In this calculation, energy loss due to electron excitation was taken into account for the atomic collision cascade after the primary knock-on process. Some parameters indispensable for the calculation such as energy loss rate, damage efficiency, projected range and its straggling were tabulated as a function of incident ion energy of 20 keV to 2 MeV. The damage and parameters were also calculated for 2 MeV nickel ions bombarding Fe targets. In this case, the DPA value is of 40--75% overestimated in a calculation disregarding electronic energy loss for primary knock-on atoms. The formula proposed in this report is significant for calculations on displacement damage produced by heavy ion bombardment as a simulation of high fluence fast neutron damage. (auth.)

  16. Calculations on displacement damage and its related parameters for heavy ion bombardment in reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Sone, K; Shiraishi, K

    1975-04-01

    The depth distribution of displacement damage expressed in displacements per atom (DPA) in reactor materials such as Mo, Nb, V, Fe and Ni bombarded by energetic nitrogen, argon and self ions with incident energy below 2 MeV was calculated following the theory developed by Lindhard and co-workers for the partition of energy as an energetic ion slowing down. In this calculation, energy loss due to electron excitation was taken into account for the atomic collision cascade after the primary knock-on process. Some parameters indispensable for the calculation such as energy loss rate, damage efficiency, projected range and its straggling were tabulated as a function of incident ion energy of 20 keV to 2 MeV. The damage and parameters were also calculated for 2 MeV nickel ions bombarding Fe targets. In this case, the DPA value is of 40--75% overestimated in a calculation disregarding electronic energy loss for primary knock-on atoms. The formula proposed in this report is significant for calculations on displacement damage produced by heavy ion bombardment as a simulation of high fluence fast neutron damage.

  17. Production of the Ne Auger electrons by Ne/sup +/ bombardment of Mg and Al surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ferrante, J; Pepper, S V [National Aeronautics and Space Administration, Cleveland, Ohio (USA). Lewis Research Center

    1976-07-01

    The authors have bombarded Mg and Al surfaces with Ne/sup +/ ions and in this letter present evidence for the production of an inner shell vacancy in the Ne by the asymmetric Ne-Mg and Ne-Al collision. In addition, autoionization states of neutral Ne have been observed. These states are to be distinguished from the more usual case in Auger electron spectroscopy of de-excitation of an ion with a core vacancy.

  18. Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K., E-mail: k.prakrajang@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K.; Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanichapichart, P. [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90112 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2012-09-01

    This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 10{sup 15} to 10{sup 16} ions/cm{sup 2}. The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

  19. Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

    International Nuclear Information System (INIS)

    Prakrajang, K.; Sangwijit, K.; Anuntalabhochai, S.; Wanichapichart, P.; Yu, L.D.

    2012-01-01

    This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 10 15 to 10 16 ions/cm 2 . The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

  20. Peculiarities of phase transformations in molybdenum-silicon system under ion bombardment

    International Nuclear Information System (INIS)

    Gurskij, L.I.; Zelenin, V.A.; Bobchenok, Yu.L.

    1984-01-01

    The problems of effect of ion bombardment and thermal treatment on the mechanisms of formation of transition layers and structural transformations in the molybdenum-silicon system, where the interface is subjected to ion bombardment through a film of molybdenum, are considered. The method of electron diffraction analysis has been applied to establish that at the molybdenum-silicon interface a transitional region appears during irradiation which has a semiamorphous structure at the doses up to 8x10 14 ion/cm 2 , while at higher doses it transforms into polycrystalline intermediate layer which consists of MoB and the compound close in composition to MoSisub(0.65). Due to thermal treatment for 60873 K a large-grain phase (Mo 3 Si+MoSi 2 ) appears in the transition layer below which a large-grain silicon layer is placed

  1. Model to estimate fractal dimension for ion-bombarded materials

    Energy Technology Data Exchange (ETDEWEB)

    Hu, A., E-mail: hu77@purdue.edu; Hassanein, A.

    2014-03-15

    Comprehensive fractal Monte Carlo model ITMC-F (Hu and Hassanein, 2012 [1]) is developed based on the Monte Carlo ion bombardment simulation code, i.e., Ion Transport in Materials and Compounds (ITMC) code (Hassanein, 1985 [2]). The ITMC-F studies the impact of surface roughness on the angular dependence of sputtering yield. Instead of assuming material surfaces to be flat or composed of exact self-similar fractals in simulation, we developed a new method to describe the surface shapes. Random fractal surfaces which are generated by midpoint displacement algorithm and support vector machine algorithm are combined with ITMC. With this new fractal version of ITMC-F, we successfully simulated the angular dependence of sputtering yield for various ion-target combinations, with the input surface roughness exponent directly depicted from experimental data (Hu and Hassanein, 2012 [1]). The ITMC-F code showed good agreement with the experimental data. In advanced, we compare other experimental sputtering yield with the results from ITMC-F to estimate the surface roughness exponent for ion-bombarded material in this research.

  2. Composition and structure of ion-bombardment-induced growth cones on InP

    International Nuclear Information System (INIS)

    Malherbe, J.B.; Lakner, H.; Gries, W.H.

    1991-01-01

    The previously reported effect of low-energy (several keV) ion bombardment on the surface topography of InP was investigated by scanning transmission electron microscopy. Convergent beam electron diffraction patterns of the surface growth 'cones' induced by argon ion bombardment of (100) InP between 7 and 10 keV proved the cones to consist of crystalline InP (and not metallic indium, as has sometimes been claimed). The investigation showed that the irradiated surface region is not rendered completely amorphous but that it recrystallizes from the crystalline/amorphous interface in a columnar growth pattern, often terminating in growth cones protruding above the surface. Weak beam investigations revealed that the overwhelming majority of the cones have the orientation of the substrate. These phenomena were observed at all dose densities from 7 x 10 15 to 2 x 10 17 cm -2 . (author)

  3. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Energy Technology Data Exchange (ETDEWEB)

    Semsang, Nuananong, E-mail: nsemsang@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, LiangDeng [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► Ion beam bombarded rice seeds in vacuum. ► Studied seed survival from the ion bombardment. ► Determined various antioxidant enzyme activities and lipid peroxidation level. ► Discussed vacuum, ion species and ion energy effects. ► Attributed the changes to free radical formation due to ion bombardment. -- Abstract: Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29–60 keV and ion fluences of 1 × 10{sup 16} ions cm{sup −2}. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  4. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Science.gov (United States)

    Semsang, Nuananong; Yu, LiangDeng

    2013-07-01

    Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  5. Structural and magnetic properties of ion-beam bombarded Co/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Lin, K.W.; Guo, J.Y.; Lin, S.R.; Ouyang, H. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402 (China); Tsai, C.J. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300 (China); Van Lierop, J. [Department of Physics and Astronomy, University of Manitoba, Winnipeg (Canada); Phuoc, N.N.; Suzuki, T. [Information Storage Materials Laboratory, Toyota Technological Institute, Nagoya 468-8511 (Japan)

    2007-12-15

    A series of [Pt(2 nm)/Co(2 nm)]{sub 10}/Pt(30 nm) multilayers were deposited by using an ion-beam technique. X-ray diffraction and transmission electron microscopy results have shown that as-deposited samples consist of h.c.p. Co and f.c.c. Pt phases. Disordered CoPt{sub 3} phases were developed with increasing End-Hall voltage (V{sub EH}) that induces greater ion-beam bombardment energy during deposition. This indicates that intermixing of Co and Pt increases with ion-beam bombardment. The coercivities (ranging from 100 Oe to 300 Oe) of Co/Pt multilayers decreased with increasing V{sub EH}. After annealing, the formation of CoPt{sub 3} was observed in these ion-beam bombarded samples, resulting in lower coercivities (H{sub c}{proportional_to} 50 Oe). The depressed transition temperature of CoPt{sub 3} for films deposited with the largest V{sub EH} was attributed to distorted CoPt{sub 3} structures that appeared with annealing. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. The crystalline-to-amorphous transition in ion-bombarded silicon

    International Nuclear Information System (INIS)

    Mueller, G.; Kalbitzer, S.

    1980-01-01

    Hydrogen-free, but defect-rich a-Si can be obtained by ion bombardment of c-Si. The formation of such material has been studied in detail using carrier-removal measurements in the characterization of the bombardment damage. In order to develop an overall view of the disordering process these data are discussed together with results obtained on similar films by Rutherford back-scattering, electron spin resonance, electron microscopy and optical measurements. It is concluded that amorphous material generally evolves from an intermediate crystalline phase supersaturated with point defects. The transition occurs locally at the sites of energetic ion impacts into critically predamaged crystalline material. As a consequence, an amorphous layer is built up from small clusters with dimensions typically of the order of 50 A. From the net expansion of the bombarded layers it is concluded that regions of lower atomic density are locally present, very likely a consequence of a structural mismatch between individual amorphous clusters. In this way a heterogeneous defect structure may build up in these films which determines their electronic properties. (author)

  7. Facies of ion bombarded surfaces of brittle materials

    International Nuclear Information System (INIS)

    Primak, W.

    1975-12-01

    Materials were bombarded by protons, deuterons, and helium ions. The materials investigated were quartz; glasses; carbides and borides (SiC, B 4 C, TiB 2 ); oxides and nitrides (magnorite, sapphire, spinel, Al 2 O 3 , Si 3 N 4 , ZrO 2 , BaTiO 3 ); and miscellaneous (graphite, LiNbO 3 , copper). Oberservations were of growth, reflectivity, blistering, surface ablation, and swelling. Calculations were made of the effects of a layer, of its gradual transformation, and of the introduction of a gas. It is concluded that: Radiation blistering is not a primary process. Observations of blister formation and exfoliation cannot be used to calculate the surface ablation rate. The primary process is the development of a microporous layer which causes swelling. Visible blisters are caused by fracturing by transverse stresses in this layer and may occur during the bombardment, or in some cases, much later, in storage. There is no evidence of extreme gas pressures in the blisters. When blisters develop, they may be stable under continued bombardment for a dose many times that at which they formed. The swelling is a better index of the effects than is the blistering, and must be associated in most cases with permeability to the gas. Behavior with protons and deuterons is similar, with helium different. All but quartz, vitreous silica, and Pyrex are impervious to hydrogen and deuterium; only dense barium crown glass, carbides, borides, oxides, and nitrides are impervious to helium. Quartz shows swelling caused by conversion to a vitreous product of much lower density but no porosity, while for the others, most of the swelling and surface growth is caused by porosity. Surface ablation by the blistering process may be reduced by initial porosity or by initial or subsequent surface fissuring. However, for impervious materials, surface damage by the introduction of porosity would continue

  8. Chemical changes in titanate surfaces induced by Ar+ ion bombardment

    International Nuclear Information System (INIS)

    Gonzalez-Elipe, A.R.; Fernandez, A.; Espinos, J.P.; Munuera, G.; Sanz, J.M.

    1992-01-01

    The reduction effects and compositional changes induced by 3.5 keV Ar + bombardment of several titanates (i.e. SrTiO 3 , Al 2 TiO 5 and NiTiO 3 ) have been quantitatively investigated by XPS. In all the samples studied here the original Ti 4+ species were reduced to lower oxidation states (i.e. Ti 3+ and Ti 2+ ), although to a lesser extent than in pure TiO 2 . On the contrary, whereas Sr 2+ and Al 3+ seem to remain unaffected by Ar + bombardment, in agreement with the behaviour of the respective oxides (i.e. SrO and Al 2 O 3 ), Ni 2+ appears more easily reducible to Ni o in NiTiO 3 than in NiO. In addition, other specific differences were observed between the titanates, which reveal the existence of interesting chemical effects related to the presence of the different counter-ions in the titanates. In the case of Al 2 TiO 5 , its Ar + -induced decomposition to form TiO 2 + Al 2 O 3 could be followed by XPS. (Author)

  9. Engineering catalytic activity via ion beam bombardment of catalyst supports for vertically aligned carbon nanotube growth

    Science.gov (United States)

    Islam, A. E.; Nikolaev, P.; Amama, P. B.; Zakharov, D.; Sargent, G.; Saber, S.; Huffman, D.; Erford, M.; Semiatin, S. L.; Stach, E. A.; Maruyama, B.

    2015-09-01

    Carbon nanotube growth depends on the catalytic activity of metal nanoparticles on alumina or silica supports. The control on catalytic activity is generally achieved by variations in water concentration, carbon feed, and sample placement on a few types of alumina or silica catalyst supports obtained via thin film deposition. We have recently expanded the choice of catalyst supports by engineering inactive substrates like c-cut sapphire via ion beam bombardment. The deterministic control on the structure and chemistry of catalyst supports obtained by tuning the degree of beam-induced damage have enabled better regulation of the activity of Fe catalysts only in the ion beam bombarded areas and hence enabled controllable super growth of carbon nanotubes. A wide range of surface characterization techniques were used to monitor the catalytically active surface engineered via ion beam bombardment. The proposed method offers a versatile way to control carbon nanotube growth in patterned areas and also enhances the current understanding of the growth process. With the right choice of water concentration, carbon feed and sample placement, engineered catalyst supports may extend the carbon nanotube growth yield to a level that is even higher than the ones reported here, and thus offers promising applications of carbon nanotubes in electronics, heat exchanger, and energy storage.

  10. Ion bombardment effects on surface states in selected oxide systems: rutile and alkaline earth titanates

    International Nuclear Information System (INIS)

    Gruen, D.M.

    1978-01-01

    In this paper, the nature of the surface states of n-type TiO 2 and SrTiO 3 is discussed and the role of ion bombardment in modifying the properties of these states is elucidated. Insofar as possible, the interrelationships between oxide nonstoichiometry, surface states, ion bombardment effects and photoelectrolysis are explored

  11. Study of the secondary electron emission during bombardment of metal targets by positive D{sup +} and D{sub 2}{sup +} ions (1960); Etude de l'emission secondaire d'electrons au cours du bombardement de cibles metalliques par des ions positifs D{sup +} et D{sub 2}{sup +} (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Leroy, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Prelec, K [Institut Rudjer Boskovic, Zagreb (Croatia)

    1960-07-01

    The secondary electron yield {gamma}-bar due to primary positive ions D{sup +} and D{sup +}{sub 2} has been measured in the 70 keV to 300 keV ion energy range. Several metallic targets have been used. The variation of this yield with the angle of incidence is proportional to sec {theta} where {theta} is the angle between the beam of primary ions and the normal to the target surface. The values {gamma}-bar decrease for increasing energy ions. At a given energy all the targets tried gave approximately the same electron yield. (author) [French] Le facteur d'emission secondaire a ete mesure pour des ions positifs D{sup +} et D{sup +}{sub 2} ayant une energie comprise entre 70 keV et 300 keV, sur differentes cibles metalliques. La variation de ce facteur avec l'angle d'incidence suit une loi de la forme {gamma}{sub 0} sec {theta}, {theta} etant l'angle entre le faisceau et la normale a la cible. Les valeurs de {gamma}-bar trouvees decroissent lorsque l'energie des ions incidents augmente, mais sont assez voisines les unes des autres, a une energie donnee, pour les differentes cibles essayees. (auteur)

  12. Considerations about projectile and target X-rays induced during heavy ion bombardment

    Science.gov (United States)

    Fernandes, F.; Bauer, D. V.; Duarte, A.; Ferrari, T. M.; Niekraszewicz, L. A. B.; Amaral, L.; Dias, J. F.

    2018-02-01

    In this work we present some results concerning the X-rays emitted by heavy ions during target bombardment. In this case, Cl4+ and Cl5+ ions with energies from 4 MeV to 10 MeV were employed to irradiate vitreous carbon planchets. Moreover, total X-ray production cross sections of titanium X-rays induced by chlorine ions were obtained as well for the same energy range. Only inner shell transitions were considered in the present work. The titanium target consisted of a thin film deposited over vitreous carbon planchets. The results indicate that the projectile X-ray yields increase as a function of the bombarding energy for the present energy range. Effects due to projectile charge state appears to be of minor importance at these low ion velocities. It is shown that a simple exponential function can represent the continuum background of such complex spectra. The chlorine transition rates Kβ/Kα obtained from chlorine acting as a projectile interacting with a carbon target are about half the value when compared to the chlorine Kβ/Kα ratios obtained when a LiCl target is bombarded with C+ and C3+ ions with energies from 2 MeV to 6 MeV. As far as the total X-ray production cross sections of Ti induced by chlorine ions are concerned, the ECPSSR theory underestimates the Ti total X-rays production cross sections by several orders of magnitude. The role of electron capture and possible mechanisms responsible for these effects are discussed.

  13. Particle-In-Cell/Monte Carlo Simulation of Ion Back Bombardment in Photoinjectors

    International Nuclear Information System (INIS)

    Qiang, Ji; Corlett, John; Staples, John

    2009-01-01

    In this paper, we report on studies of ion back bombardment in high average current dc and rf photoinjectors using a particle-in-cell/Monte Carlo method. Using H 2 ion as an example, we observed that the ion density and energy deposition on the photocathode in rf guns are order of magnitude lower than that in a dc gun. A higher rf frequency helps mitigate the ion back bombardment of the cathode in rf guns

  14. Effects produced in GaAs by MeV ion bombardment

    International Nuclear Information System (INIS)

    Wie, C.R.

    1985-01-01

    The first part of this thesis presents work performed on the ionizing energy beam induced adhesion enhancement of thin (approx.500 A) Au films on GaAs substrates. The ionizing beam, employed in the present thesis, is the MeV ions (i.e., 16 O, 19 F, and 35 Cl), with energies between 1 and 20 MeV. Using the Scratch test for adhesion measurement, and ESCA for chemical analysis of the film substrate interface, the native oxide layer at the interface is shown to play an important role in the adhesion enhancement by the ionizing radiation. A model is discussed that explains the experimental data on the dependence of adhesion enhancement on the energy which was deposited into electronic processes at the interface. The second part of the thesis presents research results on the radiation damage in GaAs crystals produced by MeV ions. Lattice parameter dilatation in the surface layers of the GaAs crystals becomes saturated after a high dose bombardment at room temperature. The strain produced by nuclear collisions is shown to relax partially due to electronic excitation (with a functional dependence on the nuclear and electronic stopping power of bombarding ions. Data on the GaAs and GaP crystals suggest that low temperature recovery stage defects produce major crystal distortion

  15. Ion bombardment induced topography evolution on low index crystal surfaces of Cu and Pb

    International Nuclear Information System (INIS)

    Tanovic, L.; Tanovic, N.; Carter, G.; Nobes, M.J.

    1993-01-01

    (100), (110) and (111) oriented single crystal surfaces of Cu and Pb have been bombarded with inert gas ions, self ions, ions of the other substrate species and Bi in the energy range 50-150 keV and in the fluence range 10 15 -10 18 ions.cm 2 . The evolving surface topography was observed by scanning electron microscopy. This topography was observed to be strongly influenced by ion species and surface orientation but the habit of the topography was delineated at low fluences and the features increased in size and density with increasing fluence with some mutation to the more stable of the features. As an example Bi and Pb bombardment of (100) Cu leads to little topographic evolution, (110) Cu develops a system of parallel ridges with (100) facets and (111) Cu develops a prismatic surface, each prism possessing (100) facets. These, and the more general, results cannot be explained by surface erosion by sputtering theory alone (this predicts surface stability of the lowest sputtering yield orientation (110), nor by surface free energy density minimisation criteria (this predicts stability of (111) surfaces). It is proposed that the observed topography is most strongly related to the crystallographic form of precipitates of implanted species. (orig.)

  16. Nucleation and growth of defects in heavy-ion and electron-bombarded metals. Final report for the period ending February 29, 1980

    International Nuclear Information System (INIS)

    Kulcinski, G.L.

    1983-04-01

    He preinjection was found to be essential in nucleating voids in high-purity Al. Interstitial pickup in high-purity V was found to be important even under good vacuum (10 - 6 to 10 - 7 torr). Voids were found to form in V down to 200 0 C. A model was tested against rdiation disordering/ordering in Cu 3 Au. Disordering in CuPd was studied. A small negative heavy ion source (SNICS) was developed for the tandem accelerator

  17. AES, EELS and TRIM simulation method study of InP(100 subjected to Ar+, He+ and H+ ions bombardment.

    Directory of Open Access Journals (Sweden)

    Abidri B.

    2012-06-01

    Full Text Available Auger Electron Spectroscopy (AES and Electron Energy Loss Spectroscopy (EELS have been performed in order to investigate the InP(100 surface subjected to ions bombardment. The InP(100 surface is always contaminated by carbon and oxygen revealed by C-KLL and O-KLL AES spectra recorded just after introduction of the sample in the UHV spectrometer chamber. The usually cleaning process of the surface is the bombardment by argon ions. However, even at low energy of ions beam (300 eV indium clusters and phosphorus vacancies are usually formed on the surface. The aim of our study is to compare the behaviour of the surface when submitted to He+ or H+ ions bombardment. The helium ions accelerated at 500V voltage and for 45 mn allow removing contaminants but induces damaged and no stoichiometric surface. The proton ions were accelerated at low energy of 500 eV to bombard the InP surface at room temperature. The proton ions broke the In-P chemical bonds to induce the formation of In metal islands. Such a chemical reactivity between hydrogen and phosphorus led to form chemical species such as PH and PH3, which desorbed from the surface. The chemical susceptibly and the small size of H+ advantaged their diffusion into bulk. Since the experimental methods alone were not able to give us with accuracy the disturbed depth of the target by these ions. We associate to the AES and EELS spectroscopies, the TRIM (Transport and Range of Ions in Matter simulation method in order to show the mechanism of interaction between Ar+, He+ or H+ ions and InP and determine the disturbed depth of the target by argon, helium or proton ions.

  18. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, L.D., E-mail: yuld@thep-center.org [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Phanchaisri, B. [Institute of Science and Technology Research, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Singkarat, S. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-05-01

    Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence.

  19. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    International Nuclear Information System (INIS)

    Yu, L.D.; Sangwijit, K.; Prakrajang, K.; Phanchaisri, B.; Thongkumkoon, P.; Thopan, P.; Singkarat, S.; Anuntalabhochai, S.

    2014-01-01

    Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence

  20. The new generations of power components will depend on neutron and/or electron bombardment techniques

    International Nuclear Information System (INIS)

    Lilen, H.

    1976-01-01

    Neutron and electron bombardment techniques for materials doping, newly introduced in the fabrication of power semiconductor components: diodes, transistors, thyristors, and triacs are briefly outlined. A neutron bombardment of high purity silicon results in a short-lived 31 Si isotope (from 30 Si) decaying into 31 P. The phosphorus with its five peripheral electrons induces a negative doping (N), and the neutron technique gives a homogeneous doping. Furthermore, silicon bombardment with 1 to 2MeV electrons induces micro-ruptures in the lattice, that act as recombination traps reducing carrier lifetimes. Consequently, gold diffusion techniques can be replaced by electron bombardment with a gain in controlling carrier lifetimes [fr

  1. Very low-energy and low-fluence ion beam bombardment of naked plasmid DNA

    International Nuclear Information System (INIS)

    Norarat, R.; Semsang, N.; Anuntalabhochai, S.; Yu, L.D.

    2009-01-01

    Ion beam bombardment of biological organisms has been recently applied to mutation breeding of both agricultural and horticultural plants. In order to explore relevant mechanisms, this study employed low-energy ion beams to bombard naked plasmid DNA. The study aimed at simulation of the final stage of the process of the ion beam bombardment of real cells to check whether and how very low-energy and low-fluence of ions can induce mutation. Argon and nitrogen ions at 5 keV and 2.5 keV respectively bombarded naked plasmid DNA pGFP to very low-fluences, an order of 10 13 ions/cm 2 . Subsequently, DNA states were analyzed using electrophoresis. Results provided evidences that the very low-energy and low-fluence ion bombardment indeed altered the DNA structure from supercoil to short linear fragments through multiple double strand breaks and thus induced mutation, which was confirmed by transfer of the bombarded DNA into bacteria Escherichia coli and subsequent expression of the marker gene.

  2. The interpretation of ellipsometric measurements of ion bombardment of noble gases on semiconductor surfaces

    NARCIS (Netherlands)

    Holtslag, A.H.M.; Slager, U.C.; van Silfhout, Arend

    1985-01-01

    Low energy noble gas ion bombardment and thermal desorption studies were carried out on Si(111) and analysed, in situ, using spectroscopic ellipsometry. The amorphous layer thickness and implanted noble gas fraction were calculated.

  3. Topography of InP surface bombarded by O2+ ion beam

    International Nuclear Information System (INIS)

    Sun Zhaoqi

    1997-01-01

    The topography of InP surface bombarded by O 2 + ion beam was investigated. Rippled topographies were observed for bombarded samples, and the data show that the ripple formation starts from a sputtering depth of about 0.4 μm. The wavelength and the disorder of the ripples both increase as the sputtering depth increases. The wavelength of the ripples appears to be sputtering depth dependent rather than sputtering rate dependent. It is confirmed that the ion-beam-induced surface rippling can be effectively suppressed by sample rotation during bombardment

  4. Effect of the ion bombardment on the apparent barrier height in GaAs Schottky junctions

    International Nuclear Information System (INIS)

    Horvath, Zs. J.

    1994-01-01

    The bombardment of the semiconductor with different particles often results in the change of the doping concentration at the semiconductor surface. In this paper the effects of this near-interface concentration change on the apparent and real Schottky barrier heights are discussed. Experimental results obtained in GaAs Schottky junctions prepared on ion-bombarded semiconductor surfaces are analysed, and it is shown that their electrical characteristics are strongly influenced by the near-interface concentration change due to the ion bombardment. (author). 36 refs., 2 figs

  5. Secondary electron ion source neutron generator

    Science.gov (United States)

    Brainard, John P.; McCollister, Daryl R.

    1998-01-01

    A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter. The target contains occluded deuterium, tritium, or a mixture thereof

  6. Influence of the ion bombardment of O{sub 2} plasmas on low-k materials

    Energy Technology Data Exchange (ETDEWEB)

    Verdonck, Patrick, E-mail: verdonck@imec.be [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Samara, Vladimir [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Open University, Materials Engineering, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Goodyear, Alec [Open University, Materials Engineering, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Ferchichi, Abdelkarim; Van Besien, Els; Baklanov, Mikhail R. [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Braithwaite, Nicholas [Open University, Department of Physics and Astronomy, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2011-10-31

    In this study, special tests were devised in order to investigate the influence of ion bombardment on the damage induced in low-k dielectrics by oxygen plasmas. By placing a sample that suffered a lot of ion bombardment and one which suffered little ion bombardment simultaneously in the same plasma, it was possible to verify that ion bombardment in fact helped to protect the low-k film against oxygen plasma induced damage. Exhaustive analyses (ellipsometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, porosimetry, capacitance-voltage (C-V) measurements, water contact angle analysis) show that ion bombardment induced the formation of a denser top layer in the film, which then hampered further penetration of active oxygen species deeper into the bulk. This was further confirmed by other tests combining capacitively and inductively coupled plasmas. Therefore, it was possible to conclude that, at least for these plasmas, ion bombardment may help to reduce plasma induced damage to low-k materials.

  7. Effect of helium ion bombardment on hydrogen behaviour in stainless steel

    International Nuclear Information System (INIS)

    Guseva, M.I.; Stolyarova, V.G.; Gorbatov, E.A.

    1987-01-01

    The effect of helium ion bombardment on hydrogen behaviour in 12Kh18N10T stainless steel is investigated. Helium and hydrogen ion bombardment was conducted in the ILU-3 ion accelerator; the fluence and energy made up 10 16 -5x10 17 cm -2 , 30 keV and 10 16 -5x10 18 cm -2 , 10 keV respectively. The method of recoil nuclei was used for determination of helium and hydrogen content. Successive implantation of helium and hydrogen ions into 12Kh18N10T stainless steel results in hydrogen capture by defects formed by helium ions

  8. Self-Assembled Gold Nano-Ripple Formation by Gas Cluster Ion Beam Bombardment.

    Science.gov (United States)

    Tilakaratne, Buddhi P; Chen, Quark Y; Chu, Wei-Kan

    2017-09-08

    In this study, we used a 30 keV argon cluster ion beam bombardment to investigate the dynamic processes during nano-ripple formation on gold surfaces. Atomic force microscope analysis shows that the gold surface has maximum roughness at an incident angle of 60° from the surface normal; moreover, at this angle, and for an applied fluence of 3 × 10 16 clusters/cm², the aspect ratio of the nano-ripple pattern is in the range of ~50%. Rutherford backscattering spectrometry analysis reveals a formation of a surface gradient due to prolonged gas cluster ion bombardment, although the surface roughness remains consistent throughout the bombarded surface area. As a result, significant mass redistribution is triggered by gas cluster ion beam bombardment at room temperature. Where mass redistribution is responsible for nano-ripple formation, the surface erosion process refines the formed nano-ripple structures.

  9. The effects of argon ion bombardment on the corrosion resistance of tantalum

    Science.gov (United States)

    Ramezani, A. H.; Sari, A. H.; Shokouhy, A.

    2017-02-01

    Application of ion beam has been widely used as a surface modification method to improve surface properties. This paper investigates the effect of argon ion implantation on surface structure as well as resistance against tantalum corrosion. In this experiment, argon ions with energy of 30 keV and in doses of 1 × 1017-10 × 1017 ions/cm2 were used. The surface bombardment with inert gases mainly produces modified topography and morphology of the surface. Atomic Force Microscopy was also used to patterned the roughness variations prior to and after the implantation phase. Additionally, the corrosion investigation apparatus wear was applied to compare resistance against tantalum corrosion both before and after ion implantation. The results show that argon ion implantation has a substantial impact on increasing resistance against tantalum corrosion. After the corrosion test, scanning electron microscopy (SEM) analyzed the samples' surface morphologies. In addition, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. The purpose of this paper was to obtain the perfect condition for the formation of tantalum corrosion resistance. In order to evaluate the effect of the ion implantation on the corrosion behavior, potentiodynamic tests were performed. The results show that the corrosion resistance of the samples strongly depends on the implantation doses.

  10. High Energy Ion Bombardment Simulation Facility at the University of Pittsburgh

    International Nuclear Information System (INIS)

    McGruer, J.N.; Choyke, W.J.; Doyle, N.J.; Spitznagel, J.A.

    1975-01-01

    The High Energy Ion Bombardment Simulation (HEIBS) Facility located at the University of Pittsburgh is now operational. The E-22 tandem accelerator of the Nuclear Physics Laboratory, fitted with a UNIS source, provides the heavy high energy ions. An auxiliary Van de Graaff accelerator is used for the simultaneous production of He ions. Special features of the simulation laboratory are reported

  11. Ion bombardment effects on the fatigue life of stainless steel under simulated fusion first wall conditions

    International Nuclear Information System (INIS)

    Kohse, G.; Harling, O.K.

    1983-01-01

    Pressurized tube specimens have been exposed to simultaneous multi-energy surface ion bombardment, fast neutron irradiation and stress and temperature cycling, in a simulation of a possible fusion reactor first wall environment. After ion bombardments equivalent to months-years of reactor operation and up to 30,000 cycles, no detrimental effects on post-irradiation fatigue life were found. The ion damage is found to enhance surface cracking, but this effect is limited to the several micron surface layer in which the ions are implanted

  12. Compositional disordering of GaAs/AlGaAs multiple quantum wells using ion bombardment at elevated temperatures

    International Nuclear Information System (INIS)

    Anderson, K.K.; Donnelly, J.P.; Wang, C.A.; Woodhouse, J.D.; Haus, H.A.

    1988-01-01

    A new method has been developed for compositional mixing of heterostructures by ion bombardment at elevated temperatures. Complete mixing of a 1-μm-thick GaAs/AlGaAs 40-period multiple quantum well layer has been achieved by bombardment with 380 keV Ne + ions for 1 h with the sample at 700 0 C. This temperature is much lower than the annealing temperatures used in other vacancy-enhanced disordering techniques, and even lower temperatures and shorter durations should be possible. Compositional disordering is verified by sputter-profile Auger electron spectroscopy and transmission electron microscopy. Complete mixing is also demonstrated by optical transmission spectra of the disordered material, which exhibit the same band edge as a uniform alloy with the average aluminum mole fraction of the multiple quantum well layer

  13. Angular dependence of secondary ion emission from silicon bombarded with inert gas ions

    International Nuclear Information System (INIS)

    Wittmaack, K.

    1984-01-01

    The emission of positive and negative, atomic and molecular secondary ions sputtered from silicon has been studied under ultrahigh vacuum conditions. The sample was bombarded with 2-12 keV Ar + and Xe + ions at angles of incidence between 0 0 and 60 0 to the surface normal. The angular dependence of the secondary ion intensity as well as the energy spectra of Si + and Si - were found to differ significantly. The effect is attributed mostly do differences in the rate of neutralization. The stability of molecular ions appears to be independent of the charge state. Supporting evidence is provided for the idea that multiply charged secondary ions are due to Auger de-excitation of sputtered atoms in vacuum. (orig.)

  14. Target bombardment by ion beams generated in the Focus experiment

    International Nuclear Information System (INIS)

    Bernard, Alain; Coudeville, Alain; Garconnet, J.-P.; Jolas, A.; Mascureau, J. de; Nazet, Christian.

    1976-01-01

    In a Mather-Focus experiment, it was shown that 80% of the neutron emitted were generated through bombardment. The apparatus was operated with various targets at a distance of 13mm from the anode. In the low pressure regime, a deuteron beam of high energy was produced. Its emission duration was measured using a CD 2 target [fr

  15. Experimental study on the secondary emission (atomic and molecular ions, aggregates, electrons) induced by the bombardment of surfaces by means of energetic heavy ions (∼ MeV/u). Effects of the charge state of the projectiles

    International Nuclear Information System (INIS)

    Monart, B.

    1988-05-01

    The ionic and electronic emissions, induced by the sputtering of solid targets (organic and inorganic) with 1 MeV/u projectiles. The time-of-flight spectrometry is applied to the secondary emission analysis. The projectile velocity, the angle of attack (between the beam and the target), and the projectile's incident charge state, are taken into account. It is shown that the secondary emission depends on the charge of the incident ion and on the charge state changement in the material's bulk. A model, applying the theoretical calculations concerning the charge in the material's bulk, is proposed. The existence of an interaction depth, for the incident ion and the material, which depends on the secondary ions type and on the incident ion charge, is suggested. The calculated depth is about 200 angstroms for the aggregates ejected from a CsI target, sputtered with 14 Kr 18+ . The H + yield (coming from ∼ 10 angstroms) is used as a projectile charge probe, at the material surface. The experimental method allows, for the first time, the obtention of the equilibrium charge state in the condensed matter. The same method is applied to determine the non-equilibrium charges in the bulk of thin materials. The results show that, after leaving the material, the projectile presents a post-ionization state [fr

  16. Effects of ion beam bombardment of carbon thin films deposited onto tungsten carbide and tool steels

    Energy Technology Data Exchange (ETDEWEB)

    Awazu, Kaoru; Yoshida, Hiroyuki [Industrial Research Inst. of Ishikawa (Japan); Watanabe, Hiroshi [Gakushuin Univ., Tokyo (Japan); Iwaki, Masaya; Guzman, L [RIKEN, Saitama (Japan)

    1992-04-15

    A study was made of the effects of argon ion bombardment of carbon thin films deposited onto WC and tool steels. Carbon thin film deposition was performed at various temperatures ranging from 200degC to 350degC, using C{sub 6}H{sub 6} gas. Argon ion beam bombardment of the films was carried out at an energy of 150 keV with a dose of 1x10{sup 16} ions cm{sup -2}. The hardness and adhesion of the films were measured by means of Knoop hardness and scratch tests respectively. The structure of the carbon films was estimated by laser Raman spectroscopy, and the relations were investigated between the mechanical properties and the structure of the films. The hardness of carbon thin films increases as their deposition temperature decreases; this tendency corresponds to the increase in amorphous structure estimated by Raman spectra. Argon ion bombardment results in constant hardness and fraction of amorphous structure. Argon ion beam bombardment of films prior to additional carbon deposition may cause the adhesion of the subsequently deposited films to improve. It is concluded that argon ion beam bombardment is useful for improving the properties of carbon films deposited onto WC and tool steels. (orig.).

  17. Effects of ion beam bombardment of carbon thin films deposited onto tungsten carbide and tool steels

    International Nuclear Information System (INIS)

    Awazu, Kaoru; Yoshida, Hiroyuki; Watanabe, Hiroshi; Iwaki, Masaya; Guzman, L.

    1992-01-01

    A study was made of the effects of argon ion bombardment of carbon thin films deposited onto WC and tool steels. Carbon thin film deposition was performed at various temperatures ranging from 200degC to 350degC, using C 6 H 6 gas. Argon ion beam bombardment of the films was carried out at an energy of 150 keV with a dose of 1x10 16 ions cm -2 . The hardness and adhesion of the films were measured by means of Knoop hardness and scratch tests respectively. The structure of the carbon films was estimated by laser Raman spectroscopy, and the relations were investigated between the mechanical properties and the structure of the films. The hardness of carbon thin films increases as their deposition temperature decreases; this tendency corresponds to the increase in amorphous structure estimated by Raman spectra. Argon ion bombardment results in constant hardness and fraction of amorphous structure. Argon ion beam bombardment of films prior to additional carbon deposition may cause the adhesion of the subsequently deposited films to improve. It is concluded that argon ion beam bombardment is useful for improving the properties of carbon films deposited onto WC and tool steels. (orig.)

  18. Structural changes IN THE Kh20N45M4B nickel alloys and THE Kh16N15M3B steel due to helium ion bombardment

    International Nuclear Information System (INIS)

    Kalin, B.A.; Chernikov, U.N.; Chernov, I.I.; Kozhevnikov, O.A.; Shishkin, G.N.; Yakushin, V.L.

    1986-01-01

    Using transmission electron microscopy, x-ray structural analysis, and the thermal desorption techniques, the authors carried out a detailed study of the structural and phase changes, defect formation, and helium accumulation in the He + -bombarded 16-15 austenitic steels and 20-45 nickel alloys. Microstructure of the bombarded specimens was studied using the methods of transmission electron microscopy of thin foils in the EVM-100, and EM-301G electron microscopes. Results of x-ray studies on the bombarded specimens are presented. The conducted studies show that bombardment of structural materials with light ions can lead to significant structural damages and changes in the chemical and phase composition of the surface layer. The possible mechanisms of the changes in the chemical and phase composition include selective sputtering and radiation-induced accelerated diffusion of elements in the field of internal lateral stresses developing during the He + implantation process

  19. Mechanism of conductivity type conversion in p-Hg1-xCdxTe crystals under low energy ion bombardment

    International Nuclear Information System (INIS)

    Bogoboyashchij, V.V.; Izhnin, I.I.

    2000-01-01

    Conditions giving rise to accelerated diffusion of Hg under bombardment of p-Hg 1-x Cd x Te by low-energy particles are analyzed and probable mechanisms of the phenomenon are suggested, permitting qualitative and quantitative agreement with experimental data. Analysis indicates that basic regularities of p-n-conversion during Hg 0.8 Cd 0.2 Te crystal bombardment by neutralized ions can be easily explained in the framework of traditional notions of mercury chemical diffusion in this material. The regularities stem from specific features of defect formation in Hg 0.8 Cd 0.2 Te, on the one hand, and from a high concentration of intrinsic electrons and holes, screening effectively the defective layer electric field, on the other hand. The high rate of conversion during ion bombardment compared with the rate of conversion during annealing in mercury vapors can be explained by the fact that a great number of nonequilibrium interstitial atoms of mercury, by far exceeding the value during thermal annealing, is crated near the surface of the crystal bombarded [ru

  20. Evolution of atomic-scale surface structures during ion bombardment: A fractal simulation

    International Nuclear Information System (INIS)

    Shaheen, M.A.; Ruzic, D.N.

    1993-01-01

    Surfaces of interest in microelectronics have been shown to exhibit fractal topographies on the atomic scale. A model utilizing self-similar fractals to simulate surface roughness has been added to the ion bombardment code TRIM. The model has successfully predicted experimental sputtering yields of low energy (less then 1000 eV) Ar on Si and D on C using experimentally determined fractal dimensions. Under ion bombardment the fractal surface structures evolve as the atoms in the collision cascade are displaced or sputtered. These atoms have been tracked and the evolution of the surface in steps of one monolayer of flux has been determined. The Ar--Si system has been studied for incidence energies of 100 and 500 eV, and incidence angles of 0 degree, 30 degree, and 60 degree. As expected, normally incident ion bombardment tends to reduce the roughness of the surface, whereas large angle ion bombardment increases the degree of surface roughness. Of particular interest though, the surfaces are still locally self-similar fractals after ion bombardment and a steady state fractal dimension is reached, except at large angles of incidence

  1. The development of cones and associated features on ion bombarded copper

    International Nuclear Information System (INIS)

    Whitton, J.L.; Carter, G.; Nobes, M.J.; Williams, J.S.

    1977-01-01

    Observations of ion-bombardment-induced surface modifications on crystalline copper substrates have been made using scanning electron microscopy. The delineation and development of grain boundary edges, faceted and terraced etch pits and small-scale ripple structure, together with the formation of faceted conical features, have all been observed on low and high purity polycrystalline substrates. In general, the density of such surface morphological features, although variable from grain to grain, is higher in the proximity of grain boundaries. In particular, cones are only found within regions where other surface erosional features are present and it would appear that the development of these other features is a pre-requisite to cone generation in high-purity crystalline substrates. We suggest the operation of a defect-induced mechanism of cone formation whereby sputter elaboration of bulk defects (either pre-existing or bombardment-induced) leads to the formation and development of surface features which, in turn, may intersect and result in the generation of cones. (author)

  2. The development of cones and associated features on ion bombarded copper

    International Nuclear Information System (INIS)

    Whitton, J.L.; Williams, J.S.

    1977-01-01

    Observations of ion-bombardment-induced surface modifications on crystalline copper substrates have been made using scanning electron microscopy. The delineation and development of grain boundary edges, faceted and terraced etch pits and small-scale ripple structure, together with the formation of faceted conical features have all been observed on low and high purity polycrystalline substrates. In general, the density of such surface morphological features, although variable from grain to grain, is higher in the proximity of grain boundaries. In particular, cones are only found within regions where other surface erosional features are present and it would appear that the development of these other surface features is a pre-requisite to cone generation in high-purity crystalline substrates. The authors suggest the operation of a defect-induced mechanism of cone formation whereby sputter elaboration of bulk defects (either preexisting or bombardment-induced) leads to the formation and development of surface features which, in turn, may intersect and result in the generation of cones. (Auth.)

  3. Photon emission produced by Kr+ ions bombardment of Cr and Cr2O3 targets

    International Nuclear Information System (INIS)

    Boujlaidi, A. El; Hammoum, K.; Jadoual, L.; Jourdani, R.; Ait El Fqih, M.; Aouchiche, H.; Kaddouri, A.

    2015-01-01

    The sputter induced photon spectroscopy technique was used to study the luminescence spectra of the species sputtered from chromium powder and its oxide Cr 2 O 3 , during 5 keV Kr + ions bombardment in vacuum better than 10 −7 torr. The optical spectra recorded between 350 and 470 nm exhibit discrete lines which are attributed to neutral excited atoms of chromium (Cr I lines). The experiments are also performed under 10 −5 torr ultra pure oxygen partial pressure. The results demonstrate that the measured intensities of the emitted photons are always higher in the presence of oxygen and even higher than those obtained for Cr 2 O 3 target. In the presence of oxygen vapor we assume that an oxide film is formed on the chromium surface which is responsible of the increase of photon emission. This variation in the intensities is correctly explained in the model of electron transfer processes between the excited sputtered atom and the bombarded surface. This model suggests that the structure formed on the Cr surface in the case of oxygenated chromium is closer to that of Cr 2 O 3 oxide

  4. Effects of low-energy ion beam bombardment on metal oxides

    International Nuclear Information System (INIS)

    Sullivan, J.L.; Saied, S.O.; Choudhury, T.

    1993-01-01

    This paper describes a study of Ar ion bombardment damage in metal oxides. In the energy range 1 to 5 keV, preferential oxygen removal and reduction of the oxides was found to depend on ion current density, but to be independent of beam energy. (author)

  5. The effect of oxygen ion beam bombardment on the properties of tin indium oxide/polyethylene terephthalate complex

    International Nuclear Information System (INIS)

    Li, Li; Liu, Honglin; Zou, Lin; Ding, Wanyu; Ju, Dongying; Chai, Weiping

    2013-01-01

    The tin indium oxide (ITO) films were deposited onto the polyethylene terephthalate (PET) surface that has been bombarded by an O ion beam. The variation of the O bombardment time resulted in the production of ITO/PET complex with different properties. Characterization by four-point probe measurement after the bending fatigue test showed that the adhesion property of the ITO/PET complex could be improved by the increase of O bombardment time while little change of electrical resistivity was observed. Scanning electron microscopy results showed that after the bending fatigue test, the nano scale seams and micro scale trenches appeared at the surface of the ITO/PET complex. The former was only the cracks of ITO film, which has little influence on the continuity and electrical resistivity of ITO film. On the contrary, the micro scale trenches were caused by the peeling off of ITO chips at the cracks, which mainly influenced the continuity and electrical resistivity of ITO film. With the increase of O bombardment time, the number and length of the micro scale trenches decreased. X-ray photoelectron spectrometry characterization showed that with the increase of O bombardment time, parts of the methylene C bonds were transformed into C=O bonds, which could be broken to form C-O-In(Sn) bonds at the initial stage of ITO film growth. By these C-O-In(Sn) crosslink bonds, the ITO film could adhere well onto the PET and the ITO/PET complex display better anti-bending fatigue property. Finally, in the context of the application of the ITO/PET complex as a flexible electrode substrate, the present work reveals a simple way to crosslink them, as well as the physicochemical mechanism happening at the interface of complex. - Highlights: • Polyethylene terephthalate (PET) surface was bombarded by N ions. • Tin indium oxide (ITO) film was deposited on bombarded PET surface. • By bombardment, methylene C bond on PET surface was broken and replaced by C=O bond. • C=O bond was

  6. The effect of oxygen ion beam bombardment on the properties of tin indium oxide/polyethylene terephthalate complex

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li; Liu, Honglin; Zou, Lin [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Ding, Wanyu, E-mail: dwysd_2000@163.com [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116028 (China); Ju, Dongying [Department of Material Science and Engineering, Saitama Institute of Technology, Fukaya 369-0293 (Japan); Chai, Weiping [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China)

    2013-10-31

    The tin indium oxide (ITO) films were deposited onto the polyethylene terephthalate (PET) surface that has been bombarded by an O ion beam. The variation of the O bombardment time resulted in the production of ITO/PET complex with different properties. Characterization by four-point probe measurement after the bending fatigue test showed that the adhesion property of the ITO/PET complex could be improved by the increase of O bombardment time while little change of electrical resistivity was observed. Scanning electron microscopy results showed that after the bending fatigue test, the nano scale seams and micro scale trenches appeared at the surface of the ITO/PET complex. The former was only the cracks of ITO film, which has little influence on the continuity and electrical resistivity of ITO film. On the contrary, the micro scale trenches were caused by the peeling off of ITO chips at the cracks, which mainly influenced the continuity and electrical resistivity of ITO film. With the increase of O bombardment time, the number and length of the micro scale trenches decreased. X-ray photoelectron spectrometry characterization showed that with the increase of O bombardment time, parts of the methylene C bonds were transformed into C=O bonds, which could be broken to form C-O-In(Sn) bonds at the initial stage of ITO film growth. By these C-O-In(Sn) crosslink bonds, the ITO film could adhere well onto the PET and the ITO/PET complex display better anti-bending fatigue property. Finally, in the context of the application of the ITO/PET complex as a flexible electrode substrate, the present work reveals a simple way to crosslink them, as well as the physicochemical mechanism happening at the interface of complex. - Highlights: • Polyethylene terephthalate (PET) surface was bombarded by N ions. • Tin indium oxide (ITO) film was deposited on bombarded PET surface. • By bombardment, methylene C bond on PET surface was broken and replaced by C=O bond. • C=O bond was

  7. Alteration of the UV-visible reflectance spectra of H2O ice by ion bombardment

    Science.gov (United States)

    Sack, N. J.; Boring, J. W.; Johnson, R. E.; Baragiola, R. A.; Shi, M.

    1991-01-01

    Satellite in the Jovian and Saturnian system exhibit differences in reflectivity between their 'leading' and 'trailing' surfaces which can affect the local vapor pressure. Since these differences are thought to be due to differences in the flux of bombarding magnetospheric ions, the influence of ion impact on the UV-visible reflectance of water ice surfaces (20-90 K) by keV ion bombardment was studied. An observed decrease in reflectance in the UV is attributed to rearrangement processes that affect the physical microstructure and surface 'roughness'. The ratio in reflectance of bombarded to freshly deposited films is compared to the ratio of the reflectance of the leading and trailing hemispheres for Europa and Ganymede.

  8. Effects of low and high energy ion bombardment on ETFE polymer

    Science.gov (United States)

    Minamisawa, R. A.; De Almeida, A.; Abidzina, V.; Parada, M. A.; Muntele, I.; Ila, D.

    2007-04-01

    The polymer ethylenetetrafluoroethylene (ETFE) is used as anti-adherent coatings for food packages and radiation dosimeters. In this work, we compare the damage induced in ETFE bombarded with 100 keV Si ions with that induced by 1 MeV proton bombardment. The damage depends on the type, energy and intensity of the irradiation. Irradiated films were analyzed with optical absorption photospectrometry, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy to determine the chemical nature of the structural changes caused by ion irradiation. Computer simulations were performed to evaluate the radiation damage.

  9. Statistical characterization of surface defects created by Ar ion bombardment of crystalline silicon

    International Nuclear Information System (INIS)

    Ghazisaeidi, M.; Freund, J. B.; Johnson, H. T.

    2008-01-01

    Ion bombardment of crystalline silicon targets induces pattern formation by the creation of mobile surface species that participate in forming nanometer-scale structures. The formation of these mobile species on a Si(001) surface, caused by sub-keV argon ion bombardment, is investigated through molecular dynamics simulation of Stillinger-Weber [Phys. Rev. B 31, 5262 (1985)] silicon. Specific criteria for identifying and classifying these mobile atoms based on their energy and coordination number are developed. The mobile species are categorized based on these criteria and their average concentrations are calculated

  10. Doubly versus singly positively charged oxygen ions back-scattered from a silicon surface under dynamic O2+ bombardment

    International Nuclear Information System (INIS)

    Franzreb, Klaus; Williams, Peter; Loerincik, Jan; Sroubek, Zdenek

    2003-01-01

    Mass-resolved (and emission-charge-state-resolved) low-energy ion back-scattering during dynamic O 2 + bombardment of a silicon surface was applied in a Cameca IMS-3f secondary ion mass spectrometry (SIMS) instrument to determine the bombarding energy dependence of the ratio of back-scattered O 2+ versus O + . While the ratio of O 2+ versus O + drops significantly at reduced bombarding energies, O 2+ back-scattered from silicon was still detectable at an impact energy (in the lab frame) as low as about 1.6 keV per oxygen atom. Assuming neutralization prior to impact, O 2+ ion formation in an asymmetric 16 O→ 28 Si collision is expected to take place via 'collisional double ionization' (i.e. by promotion of two outer O 2p electrons) rather than by the production of an inner-shell (O 2s or O 1s) core hole followed by Auger-type de-excitation during or after ejection. A molecular orbital (MO) correlation diagram calculated for a binary 'head-on' O-Si collision supports this interpretation

  11. FTIR and Vis-FUV real time spectroscopic ellipsometry studies of polymer surface modifications during ion beam bombardment

    Science.gov (United States)

    Laskarakis, A.; Gravalidis, C.; Logothetidis, S.

    2004-02-01

    The continuously increasing application of polymeric materials in many scientific and technological fields has motivated an extensive use of polymer surface treatments, which modify the physical and chemical properties of polymer surfaces leading to surface activation and promotion of the surface adhesion. Fourier transform IR spectroscopic ellipsometry (FTIRSE) and phase modulated ellipsometry (PME) in the IR and Vis-FUV spectral regions respectively have been employed for in situ and real time monitoring of the structural changes on the polymer surface obtained by Ar + ion bombardment. The polymers were industrially supplied polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) membranes. The Ar + ion bombardment has found to change the chemical bonding of the films and especially the amount of the CO, C-C and CC groups. The detailed study of the FTIRSE spectra reveals important information about the effect of the Ar + ion bombardment on each of the above bonding groups. Also, the modification of the characteristic features, attributed to electronic transitions in specific bonds of PET and PEN macromolecules, has been studied using PME.

  12. FTIR and Vis-FUV real time spectroscopic ellipsometry studies of polymer surface modifications during ion beam bombardment

    International Nuclear Information System (INIS)

    Laskarakis, A.; Gravalidis, C.; Logothetidis, S.

    2004-01-01

    The continuously increasing application of polymeric materials in many scientific and technological fields has motivated an extensive use of polymer surface treatments, which modify the physical and chemical properties of polymer surfaces leading to surface activation and promotion of the surface adhesion. Fourier transform IR spectroscopic ellipsometry (FTIRSE) and phase modulated ellipsometry (PME) in the IR and Vis-FUV spectral regions respectively have been employed for in situ and real time monitoring of the structural changes on the polymer surface obtained by Ar + ion bombardment. The polymers were industrially supplied polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) membranes. The Ar + ion bombardment has found to change the chemical bonding of the films and especially the amount of the C-O, C-C and C-C groups. The detailed study of the FTIRSE spectra reveals important information about the effect of the Ar + ion bombardment on each of the above bonding groups. Also, the modification of the characteristic features, attributed to electronic transitions in specific bonds of PET and PEN macromolecules, has been studied using PME

  13. Phenomenology of the plastic flow of amorphous solids induced by heavy-ion bombardment

    International Nuclear Information System (INIS)

    Klaumuenzer, S.; Benyagoub, A.

    1991-01-01

    Amorphous solids exhibit at temperatures far below the glass transition plastic flow when bombarded with fast heavy ions (kinetic energy ∼1 MeV/u). The dimensions perpendicular to the ion beam grow whereas the sample dimension parallel to the ion beam shrinks. The strain tensor describing phenomenologically these dimensional changes is derived from symmetry considerations and compared with experiment. Particular attention is devoted to angular changes, which have not been discussed in this context so far

  14. Kinetics of interaction from low-energy-ion bombardment of surfaces

    International Nuclear Information System (INIS)

    Horton, C.C.

    1988-01-01

    The kinetics of interaction from low energy oxygen ion bombardment of carbon and Teflon surfaces have been investigated. The surfaces were bombarded with 4.5 to 93 eV oxygen ions and emitted species were observed with a mass spectrometer. To obtain the kinetic information, the ion beam was square pulse modulated and reaction products were observed as a function of time. The kinetic information is contained in the response of the emitted species to the pulsed ion beam. Oxygen bombardment of carbon produced CO in three parallel branches with each following an adsorption-desorption process. The fast branch, with a rate constants of 12,000/sec, appeared to be sputter induced an was absent below about 19 eV. The medium and slow branches, with rate constants of 850/sec and 45/sec respectively, has little energy dependence and appeared to be due to chemical sputtering from two sites. The ratio of the fraction of the medium branch to that of the slow was constant at 1:3. The bombardment of Teflon produced CF in two parallel branches, with one following a series process and the other an adsorb-desorb process. The rate constant of the other branch were 22,000/sec and 7,000/sec and the rate constant of the other branch was 90/sec. The total signal fell monotonically with decreasing ion energy with the fraction for each branch holding constant at 71% for the series and 29% for the adsorb-desorb

  15. Ion-induced electron emission from clean metals

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Alonso, E.V.; Ferron, J.; Oliva-Florio, A.; Universidad Nacional de Cuyo, San Carlos de Bariloche

    1979-01-01

    We report recent experimental work on electron emission from clean polycrystalline metal surfaces under ion bombardment. We critically discuss existing theories and point out the presently unsolved problems. (orig.)

  16. In-Situ atomic force microscopic observation of ion beam bombarded plant cell envelopes

    International Nuclear Information System (INIS)

    Sangyuenyongpipat, S.; Yu, L.D.; Brown, I.G.; Seprom, C.; Vilaithong, T.

    2007-01-01

    A program in ion beam bioengineering has been established at Chiang Mai University (CMU), Thailand, and ion beam induced transfer of plasmid DNA molecules into bacterial cells (Escherichia coli) has been demonstrated. However, a good understanding of the fundamental physical processes involved is lacking. In parallel work, onion skin cells have been bombarded with Ar + ions at energy 25 keV and fluence1-2 x 10 15 ions/cm 2 , revealing the formation of microcrater-like structures on the cell wall that could serve as channels for the transfer of large macromolecules into the cell interior. An in-situ atomic force microscope (AFM) system has been designed and installed in the CMU bio-implantation facility as a tool for the observation of these microcraters during ion beam bombardment. Here we describe some of the features of the in-situ AFM and outline some of the related work

  17. Influence of ion bombardment on growth and properties of PLD created DLC films

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Písařík, Petr; Kocourek, Tomáš; Zemek, Josef; Lukeš, J.

    2013-01-01

    Roč. 110, č. 4 (2013), s. 943-947 ISSN 0947-8396 R&D Projects: GA MŠk LD12069 Institutional research plan: CEZ:AV0Z10100522 Keywords : DLC * ion bombardment * sp3 /sp2 * thin films * PLD Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.694, year: 2013

  18. A note on the random walk theory of recoil movement in prolonged ion bombardment

    International Nuclear Information System (INIS)

    Koponen, Ismo

    1994-01-01

    A characteristic function is derived for the probability distribution of final positions of recoil atoms in prolonged ion bombardment of dense matter. The derivation is done within the framework of Poissonian random walk theory using a jump distribution, which is somewhat more general than those studied previously. ((orig.))

  19. Oxidation under electron bombardment. A tool for studying the initial states of silicon oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Carriere, B.; Deville, J.P.; El Maachi, A.

    1987-06-01

    The exciting beam of an Auger electron spectrometer has been used to monitor the oxidation of silicon single crystals at room temperature and very low pressures of oxygen (approx. 10/sup -7/ Torr). This process allows us to build ultra-thin layers of silica on silicon (down to 30 A) but it is mostly used to investigate the mechanisms of the initial stages of oxidation. Auger spectra recorded continuously during the oxidation process provide information on (1) the nature of the silicon-oxygen chemical bonds which are interpreted through fine structure in the Auger peak, and (2) the kinetics of oxide formation which are deduced from curves of Auger signal versus time. An account is given of the contribution of these Auger studies to the description of the intermediate oxide layer during the reaction between silicon and oxygen and the influence of surface structural disorder, induced mainly by argon-ion bombardment, is discussed in terms of reactivity and oxide coverage.

  20. Comparison of Se and Te clusters produced by ion bombardment

    Directory of Open Access Journals (Sweden)

    Trzyna Małgorzata

    2017-01-01

    Full Text Available Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS. It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to ~ 1300 m/z. Local maxima or minima (magic numbers are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  1. Comparison of Se and Te clusters produced by ion bombardment

    Science.gov (United States)

    Trzyna, Małgorzata

    2017-01-01

    Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS). It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to 1300 m/z. Local maxima or minima (magic numbers) are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  2. Formation of a highly doped ultra-thin amorphous carbon layer by ion bombardment of graphene

    Science.gov (United States)

    Piotr Michałowski, Paweł; Pasternak, Iwona; Ciepielewski, Paweł; Guinea, Francisco; Strupiński, Włodek

    2018-07-01

    Ion bombardment of graphene leads to the formation of defects which may be used to tune properties of the graphene based devices. In this work, however, we present that the presence of the graphene layer on a surface of a sample has a significant impact on the ion bombardment process: broken sp2 bonds react with the incoming ions and trap them close to the surface of the sample, preventing a standard ion implantation. For an ion bombardment with a low impact energy and significant dose (in the range of 1014 atoms cm‑2) an amorphization of the graphene layer is observed but at the same time, most of the incoming ions do not penetrate the sample but stop at the surface, thus forming a highly doped ultra-thin amorphous carbon layer. The effect may be used to create thin layers containing desired atoms if no other technique is available. This approach is particularly useful for secondary ion mass spectrometry where a high concentration of Cs at the surface of a sample significantly enhances the negative ionization probability, allowing it to reach better detection limits.

  3. Films deposited from reactive sputtering of aluminum acetylacetonate under low energy ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Battaglin, Felipe Augusto Darriba; Prado, Eduardo Silva; Cruz, Nilson Cristino da; Rangel, Elidiane Cipriano, E-mail: elidiane@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Caseli, Luciano [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil). Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas; Silva, Tiago Fiorini da; Tabacniks, Manfredo Harri [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

    2017-07-15

    Films were deposited from aluminum acetylacetonate (Al(acac)3 ) using a methodology involving reactive sputtering and low energy ion bombardment. The plasma was generated by the application of radiofrequency power to the powder containing electrode and simultaneously, negative pulses were supplied to the electrode where the substrates were attached. It was investigated the effect of the duty cycle of the pulses (Δ) on the properties of the coatings. Association of ion bombardment to the deposition process increased film thickness, structure reticulation and organic content. Ions from the deposition environment were implanted at the film-air interface or underneath it. Morphology and topography were altered depending on Δ. Considering the enhancement of Δ, it affected the flux of ions reaching the depositing interface and then the deposition rate, H content, crosslinking degree and surface microstructure. Alumina groups were detected in the infrared spectra, whereas the precipitation of amorphous alumina was confirmed by X-ray diffraction. (author)

  4. Ion bombardment induced smoothing of amorphous metallic surfaces: Experiments versus computer simulations

    International Nuclear Information System (INIS)

    Vauth, Sebastian; Mayr, S. G.

    2008-01-01

    Smoothing of rough amorphous metallic surfaces by bombardment with heavy ions in the low keV regime is investigated by a combined experimental-simulational study. Vapor deposited rough amorphous Zr 65 Al 7.5 Cu 27.5 films are the basis for systematic in situ scanning tunneling microscopy measurements on the smoothing reaction due to 3 keV Kr + ion bombardment. The experimental results are directly compared to the predictions of a multiscale simulation approach, which incorporates stochastic rate equations of the Langevin type in combination with previously reported classical molecular dynamics simulations [Phys. Rev. B 75, 224107 (2007)] to model surface smoothing across length and time scales. The combined approach of experiments and simulations clearly corroborates a key role of ion induced viscous flow and ballistic effects in low keV heavy ion induced smoothing of amorphous metallic surfaces at ambient temperatures

  5. Development and evolution of biaxial texture of rolled nickel tapes by ion beam bombardment for high Tc coated conductors

    International Nuclear Information System (INIS)

    Wang, S.S.; Wu, K.; Shi, K.; Liu, Q.; Han, Z.

    2004-01-01

    High quality YBa 2 Cu 3 O 7-x films on metallic substrates with high critical current densities well over 10 6 A/cm 2 can be prepared by the rolling assisted biaxially textured substrates (RABiTS) method. Nickel or its alloys have been used as biaxially textured substrates formed through a specific rolling and high temperature annealing procedures. In this paper, we report a newly developed process for developing biaxial texture in rolled Ni tape by argon ion beam bombardment. It is named the ion-beam structure modification (ISM) process. In the ISM processed Ni foils, X-ray diffraction ω scans showed the full width-half maximum (FWHM) value of the (2 0 0) peak was 5.7 deg. . And the electron back scattering diffraction (EBSP) analysis based on scanning electron microscopy showed good {1 0 0} cubic orientation and the mean grain size was determined as about 25 μm. The texture evolution of rolled Ni foils during ISM process is reported also. For ISM process, local temperature elevation and distribution arises from the ion bombardment, coupled with anisotropic incident ion penetration and propagation as a result of channeling effects in the metal lattice, are expected to play the major roles in the development of grain reorientation in the Ni foil. Due to the simplicity and efficiency of the ISM process, the technique shows a great promise for application in the industrial scale production of long-lengths of superconductor tapes

  6. Modelling and simulation of surface morphology driven by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Yewande, E.O.

    2006-05-02

    Non-equilibrium surfaces, at nanometer length scales, externally driven via bombardment with energetic particles are known to exhibit well ordered patterns with a variety of applications in nano-technology. These patterns emerge at time scales on the order of minutes. Continuum theory has been quite successful in giving a general picture of the processes that interplay to give the observed patterns, as well as how such competition might determine the properties of the nanostructures. However, continuum theoretical descriptions are ideal only in the asymptotic limit. The only other theoretical alternative, which happens to be more suitable for the characteristic length-and time-scales of pattern formation, is Monte Carlo simulation. In this thesis, surface morphology is studied using discrete solid-on-solid Monte Carlo models of sputtering and surface diffusion. The simulations are performed in the context of the continuum theories and experiments. In agreement with the experiments, the ripples coarsen with time and the ripple velocity exhibits a power-law behaviour with the ripple wavelength, in addition, the exponent was found to depend on the simulation temperature, which suggests future experimental studies of flux dependence. Moreover, a detailed exploration of possible topographies, for different sputtering conditions, corresponding to different materials, was performed. And different surface topographies e.g. holes, ripples, and dots, were found at oblique incidence, without sample rotation. With sample rotation no new topography was found, its only role being to destroy any inherent anisotropy in the system. (orig.)

  7. Effect of Ni +-ION bombardment on nickel and binary nickel alloys

    Science.gov (United States)

    Roarty, K. B.; Sprague, J. A.; Johnson, R. A.; Smidt, F. A.

    1981-03-01

    Pure nickel and four binary nickel alloys have been subjected to high energy Ni ion bombardment at 675, 625 and 525°C. After irradiation, each specimen was studied by transmission electron microscopy. The pure nickel control was found to swell appreciably (1 to 5%) and the Ni-Al and the Ni-Ti samples were found to swell at all temperatures, but to a lesser degree (0.01 to 0.35%). The Ni-Mo contained a significant density of voids only at 525° C, while swelling was suppressed at all temperatures in the Ni-Si alloy. The dislocation structure progressed from loops to tangles as temperature increased in all materials except the Ni-Ti, in which there was an absence of loops at all temperatures. Dislocation densities decreased as temperature increased in all samples. These results do not correlate well with the relative behavior of the same alloys observed after neutron irradiation at 455°C. The differences between these two sets of data appear to be caused by different mechanisms controlling void nucleation in ion and neutron irradiation of these alloys.

  8. Silicon transport in sputter-deposited tantalum layers grown under ion bombardment

    International Nuclear Information System (INIS)

    Gallais, P.; Hantzpergue, J.J.; Remy, J.C.; Roptin, D.

    1988-01-01

    Tantalum was sputter deposited on (111) Si substrate under low-energy ion bombardment in order to study the effects of the ion energy on the silicon transport into the Ta layer. The Si substrate was heated up to 500 0 C during growth. For ion energies up to 180 eV silicon is not transported into tantalum and the growth temperature has no effect. An ion bombardment energy of 280 eV enhances the transport of silicon throughout the tantalum layer. Growth temperatures up to 300 0 C have no effect on the silicon transport which is mainly enhanced by the ion bombardment. For growth temperatures between 300 and 500 0 C, the silicon transport is also enhanced by the thermal diffusion. The experimental depth distribution of silicon is similar to the theoretical depth distribution calculated for the case of an interdiffusion. The ion-enhanced process of silicon transport is characterized by an activation energy of 0.4 eV. Silicon into the layers as-grown at 500 0 C is in both states, amorphous silicide and microcrystalline cubic silicon

  9. Forming controlled inset regions by ion implantation and laser bombardment

    International Nuclear Information System (INIS)

    Gibbons, J.F.

    1981-01-01

    A semiconductor integrated circuit structure in which the inset regions are ion implanted and laser annealed to maintain substantially the dimensions of the implantation and the method of forming inset implanted regions having controlled dimensions

  10. Study on the growth of aligned carbon nanotubes controlled by ion bombardment

    International Nuclear Information System (INIS)

    Wang Biben; Zhang Bing; Zheng Kun; Hao Wei; Wang Wanlu; Liao Kejun

    2004-01-01

    Aligned carbon nanotubes were prepared by plasma-enhanced hot filament chemical vapor deposition using CH 4 , H 2 and NH 3 as reaction gases. It was investigated how different negative bias affects the growth of aligned carbon nanotubes. The results indicate that the average diameter of the aligned carbon nanotubes is reduced and the average length of the aligned carbon nanotubes is increased with increasing negative bias. Because of the occurrence of glow discharge, a cathode sheath forms near the substrate surface, and a number of ions are produced in it, and a very strong electrical field builds up near the substrate surface. Under the effect of the field, the strong bombardment of ions on the substrate surface will influence the growth of aligned carbon nanotubes. Combined with related theories, authors have analyzed and discussed the ion bombardment effects on the growth of the aligned carbon nanotudes

  11. Heavy-ion induced desorption yields of cryogenic surfaces bombarded with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Evans, L; Kollmus, H; Küchler, D; Scrivens, R; Severin, D; Wengenroth, M; CERN. Geneva. ATS Department

    2011-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy-Ion Accelerator LINAC 3, has been used to study the dynamic outgassing of cryogenic surfaces. Two different targets, bare and goldcoated copper, were bombarded under perpendicular impact with 4.2 MeV/u Pb54+ ions. Partial pressure rises of H2, CH4, CO, and CO2 and effective desorption yields were measured at 300, 77, and 6.3 K using single shot and continuous ion bombardment techniques. We find that the heavy-ion-induced desorption yield is temperature dependent and investigate the influence of CO gas cryosorbed at 6.3 K. The gain in desorption yield reduction at cryogenic temperature vanishes after several monolayers of CO are cryosorbed on both targets. In this paper we describe the new cryogenic target assembly, the temperature-dependent pressure rise, desorption yield, and gas adsorption measurements.

  12. Ion bombardment damage in a modified Fe-9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Farrell, K.; Lee, E.H.

    1984-01-01

    A normalized-and-tempered Fe-9Cr-1Mo steel, with small Nb and V additions, was bombarded with 4-MeV iron ions to 100 dpa at 400, 450, 500, 550, and 600 0 C. Major damage feature was dislocation tangles which coarsened with increasing bombardment temperature. Sparse cavities were heterogeneously distributed at 500 and 550 0 C. Incorporation of helium and deuterium simultaneously in the bombardments at rates of 10 and 45 appM/dpa, respectively, introduced very high concentrations of small cavities at all temperatures, many of them on grain boundaries. These cavities were shown to be promoted by helium. A small fraction of the matrix cavities exhibited bias-driven growth at 500 and 550 0 C, with swelling 0 C higher than the peak swelling temperature found in neutron irradiations, which is compatible with the higher damage rate used in the ion bombardments. High concentrations of subgrain boundaries and dislocations resulting from the heat treatment, and unbalanced cavity and dislocation sink strengths in the damage structures contribute to the swelling resistance. Such resistance may not be permanent. High densities of bubbles on grain boundaries indicate a need for helium embrittlement tests

  13. XPS study of vanadium surface oxidation by oxygen ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Alov, N.; Kutsko, D.; Spirovová, Ilona; Bastl, Zdeněk

    2006-01-01

    Roč. 600, č. 8 (2006), s. 1628-1631 ISSN 0039-6028 R&D Projects: GA ČR GA104/04/0467 Institutional research plan: CEZ:AV0Z40400503 Keywords : vanadium oxide * oxide film * ion-beam oxidation * X-ray photoelectron spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.880, year: 2006

  14. Modification of metallic surfaces by positive ion bombardment

    International Nuclear Information System (INIS)

    Rickards C, J.

    1989-01-01

    Reported are the fundamentals and recent advances in the use of ion implantation techniques and gaseous emissions to modify metal surfaces. The physical phenomena involved, the necessary equipment and some applications which have been successful on an industrial scale are described. (Author). 13 refs, 1 fig

  15. Confirming the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials by PECVD.

    Science.gov (United States)

    Liu, Yulin; Lin, Jinghuang; Jia, Henan; Chen, Shulin; Qi, Junlei; Qu, Chaoqun; Cao, Jian; Feng, Jicai; Fei, Weidong

    2017-11-24

    In order to confirm the key role of Ar + ion bombardment in the growth feature of nanostructured carbon materials (NCMs), here we report a novel strategy to create different Ar + ion states in situ in plasma enhanced chemical vapor deposition (PECVD) by separating catalyst film from the substrate. Different bombardment environments on either side of the catalyst film were created simultaneously to achieve multi-layered structural NCMs. Results showed that Ar + ion bombardment is crucial and complex for the growth of NCMs. Firstly, Ar + ion bombardment has both positive and negative effects on carbon nanotubes (CNTs). On one hand, Ar + ions can break up the graphic structure of CNTs and suppress thin CNT nucleation and growth. On the other hand, Ar + ion bombardment can remove redundant carbon layers on the surface of large catalyst particles which is essential for thick CNTs. As a result, the diameter of the CNTs depends on the Ar + ion state. As for vertically oriented few-layer graphene (VFG), Ar + ions are essential and can even convert the CNTs into VFG. Therefore, by combining with the catalyst separation method, specific or multi-layered structural NCMs can be obtained by PECVD only by changing the intensity of Ar + ion bombardment, and these special NCMs are promising in many fields.

  16. Confirming the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials by PECVD

    Science.gov (United States)

    Liu, Yulin; Lin, Jinghuang; Jia, Henan; Chen, Shulin; Qi, Junlei; Qu, Chaoqun; Cao, Jian; Feng, Jicai; Fei, Weidong

    2017-11-01

    In order to confirm the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials (NCMs), here we report a novel strategy to create different Ar+ ion states in situ in plasma enhanced chemical vapor deposition (PECVD) by separating catalyst film from the substrate. Different bombardment environments on either side of the catalyst film were created simultaneously to achieve multi-layered structural NCMs. Results showed that Ar+ ion bombardment is crucial and complex for the growth of NCMs. Firstly, Ar+ ion bombardment has both positive and negative effects on carbon nanotubes (CNTs). On one hand, Ar+ ions can break up the graphic structure of CNTs and suppress thin CNT nucleation and growth. On the other hand, Ar+ ion bombardment can remove redundant carbon layers on the surface of large catalyst particles which is essential for thick CNTs. As a result, the diameter of the CNTs depends on the Ar+ ion state. As for vertically oriented few-layer graphene (VFG), Ar+ ions are essential and can even convert the CNTs into VFG. Therefore, by combining with the catalyst separation method, specific or multi-layered structural NCMs can be obtained by PECVD only by changing the intensity of Ar+ ion bombardment, and these special NCMs are promising in many fields.

  17. Selective laser-induced photochemical dry etching of semiconductors controlled by ion-bombardment-induced damage

    International Nuclear Information System (INIS)

    Ashby, C.I.H.; Myers, D.R.; Vook, F.L.

    1987-01-01

    When a photochemical dry etching process requires direct participation of photogenerated carriers in the chemical reaction, it is sensitive to the electronic properties of the semiconductor. For such solid-excitation-based dry etching processes, the balance between reaction and carrier recombination rates determines the practical utility of a particular reaction for device fabrication. The distance from the surface at which the photocarriers are generated by light adsorption is determined by the absorption coefficient. In the absence of an external bias potential, only those carriers formed within a diffusion length of the surface space-charge region will have an opportunity to drive the dry etching reaction. When the absorption coefficient is high, most of the photons generate carriers within a diffusion length from the surface space-charge region, and the etching rate is largely determined by the balance between the rate of the carrier-driven reaction and the surface recombination velocity. When the recombination rate of free carriers in the bulk of the semiconductor is high, the effective diffusion length is reduced and fewer of the carriers generated in the subsurface region ever reach the surface. An important effect of ion bombardment is the creation of many lattice defects that increase the rate of recombination of electrons and holes. When a sufficient number of defects, which act as recombination sites, are formed during ion implantation, the recombination of photogenerated carriers at these defects in the subsurface region can greatly reduce the number of carriers which can reach the surface and drive a photochemical etching reaction

  18. Study of ion-bombardment-induced surface topography of silver by stereophotogrammetric method

    International Nuclear Information System (INIS)

    Fayazov, I.M.; Sokolov, V.N.

    1992-01-01

    The ion-bombardment-induced surface topography of polycrystalline silver was studied using the stereophotogrammetric method. The samples were irradiated with 30keV argon ions at fairly high fluences (> 10 17 ions/cm 2 ). The influence of the inclination angle of the sample in the SEM on the cone shape of a SEM-picture is discussed. To analyse the irradiated surfaces covered with cones, the SEM-stereotechnique is proposed. The measurements of the sample section perpendicular to the incidence plane are also carried out. (author)

  19. Angular and energy dependence of ion bombardment of Mo/Si multilayers

    DEFF Research Database (Denmark)

    Voorma, H.J.; Louis, E.; Bijkerk, F.

    1997-01-01

    The process of ion bombardment is investigated for the fabrication of Mo/Si multilayer x-ray mirrors using e-beam evaporation. The ion treatment is applied immediately after deposition of each of the Si layers to smoothen the layers by removing an additional thickness of the Si layer. In this stu......, the angular dependence of the etch yield, obtained from the in situ reflectivity measurements, is investigated in order o determine the optimal ion beam parameters for the production of multilayer mirrors on curved substrates....

  20. Additional ion bombardment in PVD processes generated by a superimposed pulse bias voltage

    International Nuclear Information System (INIS)

    Olbrich, W.; Kampschulte, G.

    1993-01-01

    The superimposed pulse bias voltage is a tool to apply an additional ion bombardment during deposition in physical vapour deposition (PVD) processes. It is generated by the combination of a d.c. ground voltage and a higher d.c. pulse voltage. Using a superimposed pulse bias voltage in ion-assisted PVD processes effects an additional all-around ion bombardment on the surface with ions of higher energy. Both metal and reactive or inert-gas ions are accelerated to the surface. The basic principles and important characteristics of this newly developed process such as ion fluxes or deposition rates are shown. Because of pulsing the high voltage, the deposition temperature does not increase much. The adhesion, structure, morphology and internal stresses are influenced by these additional ion impacts. The columnar growth of the deposited films could be suppressed by using the superimposed pulse bias voltage without increasing the deposition temperature. Different metallizations (Cr and Cu) produced by arc and sputter ion plating are investigated. Carbon-fibre-reinforced epoxy are coated with PVD copper films for further treatment in electrochemical processes. (orig.)

  1. Measures to alleviate the back bombardment effect of thermionic rf electron gun

    International Nuclear Information System (INIS)

    Huang, Y.; Xie, J.

    1991-01-01

    Thermionic rf electron gun finds application as a high brightness electron source for rf linacs. However, cathode heating from back-bombardment effect causes a ramp in the macro-pulse beam current and limit the usable pulse width. Three methods: ring cathode, magnetic deflection and laser assisted heating are studied in theory and in experiment. The results of these studies are reported

  2. Low energy Ar ion bombardment damage of Si, GaAs, and InP surfaces

    International Nuclear Information System (INIS)

    Williams, R.S.

    1982-01-01

    Argon bombardment damage to (100) surfaces of Si, GaAs, and InP for sputter ion-gun potentials of 1, 2, and 3 kilovolts was studied using Rutherford backscattering. Initial damage rates and saturation damage levels were determined. Bombardment damage sensitivity increased for the sequence Si, GaAs, and InP. Saturation damage levels for Si and GaAs correspond reasonably to LSS projected range plus standard deviation estimates; damage to InP exceeded this level significantly. For an ion-gun potential of 3 keV, the initial sputter yield of P from an InP surface exceeded the sputter yield of In by four atoms per incident Ar projectile. (author)

  3. The Effect of Gas Ion Bombardment on the Secondary Electron Yield of TiN, TiCN and TiZrV Coatings For Suppressing Collective Electron Effects in Storage Rings

    International Nuclear Information System (INIS)

    Le Pimpec, F.; Kirby, R.E.; King, F.K.; Pivi, M.

    2006-01-01

    In many accelerator storage rings running positively charged beams, ionization of residual gas and secondary electron emission (SEE) in the beam pipe will give rise to an electron cloud which can cause beam blow-up or loss of the circulating beam. A preventative measure that suppresses electron cloud formation is to ensure that the vacuum wall has a low secondary emission yield (SEY). The SEY of thin films of TiN, sputter deposited Non-Evaporable Getters and a novel TiCN alloy were measured under a variety of conditions, including the effect of re-contamination from residual gas

  4. Titanium oxidation-reduction at low oxygen pressure under electron bombardment

    International Nuclear Information System (INIS)

    Brasca, R.; Passeggi, M.C.G.; Ferron, J.

    2006-01-01

    The effect of the electron bombardment on the first stages of the titanium oxidation process has been studied by means of Auger Electron Spectroscopy. Using Factor Analysis and the valence electron dependence behaviour of the titanium LMV Auger transition, we found that the process is strongly dependent on the oxygen pressure and electron current density. Depending on the irradiation conditions, films of different thickness and Ti oxidized states are obtained

  5. Large area smoothing of surfaces by ion bombardment: fundamentals and applications

    International Nuclear Information System (INIS)

    Frost, F; Fechner, R; Ziberi, B; Voellner, J; Flamm, D; Schindler, A

    2009-01-01

    Ion beam erosion can be used as a process for achieving surface smoothing at microscopic length scales and for the preparation of ultrasmooth surfaces, as an alternative to nanostructuring of various surfaces via self-organization. This requires that in the evolution of the surface topography different relaxation mechanisms dominate over the roughening, and smoothing of initially rough surfaces can occur. This contribution focuses on the basic mechanisms as well as potential applications of surface smoothing using low energy ion beams. In the first part, the fundamentals for the smoothing of III/V semiconductors, Si and quartz glass surfaces using low energy ion beams (ion energy: ≤2000 eV) are reviewed using examples. The topography evolution of these surfaces with respect to different process parameters (ion energy, ion incidence angle, erosion time, sample rotation) has been investigated. On the basis of the time evolution of different roughness parameters, the relevant surface relaxation mechanisms responsible for surface smoothing are discussed. In this context, physical constraints as regards the effectiveness of surface smoothing by direct ion bombardment will also be addressed and furthermore ion beam assisted smoothing techniques are introduced. In the second application-orientated part, recent technological developments related to ion beam assisted smoothing of optically relevant surfaces are summarized. It will be demonstrated that smoothing by direct ion bombardment in combination with the use of sacrificial smoothing layers and the utilization of appropriate broad beam ion sources enables the polishing of various technologically important surfaces down to 0.1 nm root mean square roughness level, showing great promise for large area surface processing. Specific examples are given for ion beam smoothing of different optical surfaces, especially for substrates used for advanced optical applications (e.g., in x-ray optics and components for extreme

  6. Investigation of energy thresholds of atomic and cluster sputtering of some elements under ion bombardment

    CERN Document Server

    Atabaev, B G; Lifanova, L F

    2002-01-01

    Threshold energies of sputtering of negative cluster ions from the Si(111) surface were measured at bombardment by Cs sup + , Rb sup + , and Na sup + ions with energy of 0.1-3.0 keV. These results are compared with the calculations of the similar thresholds by Bohdansky etc. formulas (3) for clusters Si sub n sup - and Cu sub n sup - with n=(1-5) and also for B, C, Al, Si, Fe, Cu atoms. Threshold energies of sputtering for the above elements were also estimated using the data from (5). Satisfactory agreement between the experimental and theoretical results was obtained. (author)

  7. Surface Morphologies of Ti and Ti-Al-V Bombarded by 1.0-MeV Au+ Ions

    Science.gov (United States)

    Garcia, M. A.; Rickards, J.; Cuerno, R.; Trejo-Luna, R.; Cañetas-Ortega, J.; de la Vega, L. R.; Rodríguez-Fernández, L.

    2017-12-01

    Ion implantation is known to enhance the mechanical properties of biomaterials such as, e.g., the wear resistance of orthopedic joints. Increasing the surface area of implants may likewise improve their integration with, e.g., bone tissue, which requires surface features with sizes in the micron range. Ion implantation of biocompatible metals has recently been demonstrated to induce surface ripples with wavelengths of a few microns. However, the physical mechanisms controlling the formation and characteristics of these patterns are yet to be understood. We bombard Ti and Ti-6Al-4V surfaces with 1.0-MeV Au+ ions. Analysis by scanning electron and atomic force microscopies shows the formation of surface ripples with typical dimensions in the micron range, with potential indeed for biomedical applications. Under the present specific experimental conditions, the ripple properties are seen to strongly depend on the fluence of the implanted ions while being weakly dependent on the target material. Moreover, by examining experiments performed for incidence angle values θ =8 ° , 23°, 49°, and 67°, we confirm the existence of a threshold incidence angle for (ripple) pattern formation. Surface indentation is also used to study surface features under additional values of θ , agreeing with our single-angle experiments. All properties of the surface structuring process are very similar to those found in the production of surface nanopatterns under low-energy ion bombardment of semiconductor targets, in which the stopping power is dominated by nuclear contributions, as in our experiments. We consider a continuum model that combines the effects of various physical processes as originally developed in that context, with parameters that we estimate under a binary-collision approximation. Notably, reasonable agreement with our experimental observations is achieved, even under our high-energy conditions. Accordingly, in our system, ripple formation is determined by mass

  8. Radiation effects in zinc oxide: zinc under bombardment with KeV ions

    International Nuclear Information System (INIS)

    Hastings, J.W.L.

    1967-01-01

    The energy loss, light output, depth of deterioration and the deterioration constant have been determined as a function of energy for various atomic projectiles impinging upon samples of a powdered Zn:Zn phosphor at energies below 105 KeV. The energy loss was observed as a reduction in the light output when projectiles traversed thin regions of previously damaged phosphor. The energy losses for heavier projectiles ( 14 N, 40 Ar, 84 Kr), relative to hydrogen, were found to be lower than those predicted for an amorphous stopping medium. The light output for a given projectile was found to be approximately proportional to the amount of energy lost in electronic collisions. When a phosphor is subjected to prolonged bombardment by heavy ions the deterioration depth is fairly well defined and its value was determined by a measurement of the energy loss of a hydrogen beam in traversing the damaged region. The depths are very large, are proportional to the projectile velocity and seem to be determined to a significant degree by electronic stopping. The deterioration constant, C, is a measure of the ability of a projectile to deteriorate a phosphor and its value is proportional to the number of defects introduced in unit distance along the trajectory of the projectile. The constant was determined from measurements of the efficiencies η, and η o , of partly damaged and undamaged phosphor, respectively, using the observed relationship, C (η/η o - 1) n -1 where n is the irradiation dose. The relative magnitudes of the C values for 14 N, 40 Ar were found to be in agreement with measured nuclear energy loss cross sections for these projectiles. (author)

  9. Uranium targets sandwiched between carbon layers for use on target wheels and on a Wobbler in heavy-ion bombardments

    International Nuclear Information System (INIS)

    Folger, H.; Hartmann, W.; Klemm, J.; Thalheimer, W.

    1989-01-01

    Uranium layers of ≅ 0.4 mg/cm 2 are evaporated by means of a 6 kW electron-beam gun onto 0.04 mg/cm 2 thick carbon films in a high-vacuum process; a protecting layer of ≅ 0.01 mg/cm 2 of carbon is added in the same vacuum cycle. The evaporation- and deposition yields are discussed and measurements of target characteristics are described. C/U/C sandwich targets in the shape of a sector of an annulus are prepared for use on rotating target wheels of 155 mm radius to be bombarded with a pulsed beam of heavy ions. One type of circular targets of 20 mm in diameter is mounted to a target wobbler. Both, wheel and wobbler, distribute the intensity of the heavy-ion beam to a larger area to reduce radiation damages. Examples of target applications will be mentioned. (orig.)

  10. A model for the build-up of disordered material in ion bombarded Si

    International Nuclear Information System (INIS)

    Nelson, R.S.

    1977-01-01

    A new model based on experimental observation is developed for the build-up of disordered material in ion bombarded silicon. The model assumes that disordered zones are created in a background of migrating point defects, these zones then act as neutral sinks for such defects which interact with the zones and cause recrystallization. A simple steady state rate theory is developed to describe the build-up of disordered material with ion dose as a function of temperature. In general the theory predicts two distinct behaviour patterns depending on the temperature and the ion mass, namely a linear build-up with dose to complete disorder for heavy bombarding ions and a build-up to saturation at a relatively low level for light ions such as protons. However, in some special circumstances a transition region is predicted where the build-up of disorder approximately follows a (dose)sup(1/2) relationship before reverting to a linear behaviour at high dose. (author)

  11. High-energy particle emission from galena and pyrite bombarded with Cs and O ions

    International Nuclear Information System (INIS)

    Karpuzov, D.S.; McIntyre, N.S.

    2002-01-01

    The ejection of energetic particles during steady-state ion surface bombardment has been investigated by means of a dynamic computer simulation as well as in a secondary ion mass spectrometry (SIMS)/low-energy ion scattering from surfaces (LEIS) experiment. The emphasis of this comparative study is on the mass dependence of high-energy tails in sputtering and backscattering for the bombardment of galena (PbS) and pyrite (FeS 2 ) with keV energy ion beam of cesium and oxygen. In the experiment, kinetic energy distributions of sputtered secondary ions (S + , Fe + , Pb + , S - ), as well as backscattered or re-sputtered primary ions (Cs + , O + , O - ), have been measured on a modified Cameca IMS-3f magnetic sector mass spectrometer for keV cesium (Cs + ) and oxygen (O 2 + , O - ) bombardment of galena and pyrite. Ejection of high-energy particles, with emission energies of up to ∼40% or up to ∼60% of the bombarding energy for sputtering of the lighter component (S ± ) with cesium or oxygen, respectively, and of up to ∼40% (Cs + ) and ∼80% (O ± ) for backscattering, has been observed for PbS. The computer simulations were based on the well-known MARLOWE code. In order to model the change of the stoichiometry of the binary compounds, dynamic modification of the target composition in the near-surface region was introduced. Cs incorporation was included, and a relative enrichment of the metallic component (Pb, Fe) in the top few layers due to preferential sputtering of sulfur was allowed. The computer simulations provide information on the formation of altered layer under sputter equilibrium as well as on the energy and angular emission distributions of sputtered and backscattered particles in steady-state conditions. Multiple scattering of Cs projectiles and dynamic re-sputtering of cesium that was previously incorporated in the altered near-surface region can be distinguished in the simulation, and matched with the experimental observations. In addition

  12. Proposals for the heating mechanism of an electron-bombarded body

    International Nuclear Information System (INIS)

    Geller, R.; Yerouchalmi, F.

    1967-01-01

    When a thermally isolated target in vacuum is bombarded by an electron beam the target becomes red. In this paper we try a heuristic explanation indicating how the kinetic power of the beam may be transformed into radiation power controlled by Stefan law. (authors) [fr

  13. Ion-bombardment-induced reduction in vacancies and its enhanced effect on conductivity and reflectivity in hafnium nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Zhiqing; Wang, Jiafu; Hu, Chaoquan; Zhang, Xiaobo; Dang, Jianchen; Gao, Jing; Zheng, Weitao [Jilin University, School of Materials Science and Engineering, Key Laboratory of Mobile Materials, MOE, and State Key Laboratory of Superhard Materials, Changchun (China); Zhang, Sam [Nanyang Technological University, School of Mechanical and Aerospace Engineering, Singapore (Singapore); Wang, Xiaoyi [Chinese Academy of Sciences, Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Changchun (China); Chen, Hong [Jilin University, Department of Control Science and Engineering, Changchun (China)

    2016-08-15

    Although the role of ion bombardment on electrical conductivity and optical reflectivity of transition metal nitrides films was reported previously, the results were controversial and the mechanism was not yet well explored. Here, we show that proper ion bombardment, induced by applying the negative bias voltage (V{sub b}), significantly improves the electrical conductivity and optical reflectivity in rocksalt hafnium nitride films regardless of level of stoichiometry (i.e., in both near-stoichiometric HfN{sub 1.04} and over-stoichiometric HfN{sub 1.17} films). The observed improvement arises from the increase in the concentration of free electrons and the relaxation time as a result of reduction in nitrogen and hafnium vacancies in the films. Furthermore, HfN{sub 1.17} films have always much lower electrical conductivity and infrared reflectance than HfN{sub 1.04} films for a given V{sub b}, owing to more hafnium vacancies because of larger composition deviation from HfN exact stoichiometry (N:Hf = 1:1). These new insights are supported by good agreement between experimental results and theoretical calculations. (orig.)

  14. Low temperature magnetron sputter deposition of polycrystalline silicon thin films using high flux ion bombardment

    International Nuclear Information System (INIS)

    Gerbi, Jennifer E.; Abelson, John R.

    2007-01-01

    We demonstrate that the microstructure of polycrystalline silicon thin films depends strongly on the flux of low energy ions that bombard the growth surface during magnetron sputter deposition. The deposition system is equipped with external electromagnetic coils which, through the unbalanced magnetron effect, provide direct control of the ion flux independent of the ion energy. We report the influence of low energy ( + on the low temperature ( + ions to silicon neutrals (J + /J 0 ) during growth by an order of magnitude (from 3 to 30) enables the direct nucleation of polycrystalline Si on glass and SiO 2 coated Si at temperatures below 400 degree sign C. We discuss possible mechanisms for this enhancement of crystalline microstructure, including the roles of enhanced adatom mobility and the formation of shallow, mobile defects

  15. Topography development on selected inert gas and self-ion bombarded Si

    International Nuclear Information System (INIS)

    Vishnyakov, V.; Carter, G.; Goddard, D.T.; Nobes, M.J.

    1995-01-01

    An AFM and SEM study of the topography induced by 20 keV Si + , Ar + and Xe + ion bombardment of Si at 45 o incidence angles and for ion fluences between 10 17 and 10 20 cm -2 has been undertaken at room temperature. All species generate an atomic scale random roughness, the magnitude of which does not increase extensively with ion fluence, suggesting the operation of a local relaxation process. This nanometre scale roughness forms, for Ar and Xe, a background for coarser micrometre scale structures such as pits, chevrons and waves. Apart from isolated etch pits Si + irradiation generates no repetitive micrometre scale structures. Xe + irradiation produces well developed transverse waves while Ar + irradiation results in isolated chevron-like etch pit trains and ripple patches. This latter pattern evolves, with increasing ion fluence, to a corrugated facet structure. The reasons for the different behaviours are still not fully clarified. (author)

  16. On the modification of metal/ceramic interfaces by low energy ion/atom bombardment during film growth

    International Nuclear Information System (INIS)

    Rigsbee, J.M.; Scott, P.A.; Knipe, R.K.; Hock, V.F.

    1986-01-01

    Elemental Cu and Ti films have been deposited onto ceramic substrates with a plasma-aided physical vapor deposition (ion-plating) process. This paper discusses how the structure and chemistry of the metallic film and the metal/ceramic interface are modified by low energy ion and neutral atom bombardment. Emphasis is placed on determining how low energy ion/neutral atom bombardment affects the strength of the metal/ceramic interface. Analyses of the film, interface and substrate regions have employed scanning Auger microprobe, secondary ion mass spectroscopy, SEM/STEM-energy dispersive X-ray and TEM/STEM imaging and microdiffraction techniques. (Auth.)

  17. Ion induced high energy electron emission from copper

    International Nuclear Information System (INIS)

    Ruano, G.; Ferron, J.

    2008-01-01

    We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He + , Ne + and Ar + ) and Li + ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

  18. Chemical changes of titanium and titanium dioxide under electron bombardment

    Directory of Open Access Journals (Sweden)

    Romins Brasca

    2007-09-01

    Full Text Available The electron induced effect on the first stages of the titanium (Ti0 oxidation and titanium dioxide (Ti4+ chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+.

  19. Absorption of hydrogen in vanadium, enhanced by ion bombardment; Ionenbeschussunterstuetzte Absorption des Wasserstoffs in Vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

    1998-12-31

    Prior to hydrogen implantation into vanadium, the vanadium specimen usually is exposed to an activation process and is then heated at 1 atm hydrogen to temperatures between 500 and 600 C, subsequently cooled down in several steps. Within this temperature range, hydrogen solubility increases with declining temperature. A decisive factor determining hydrogen absorption is the fact that at temperatures above 250 C, oxygen desorbs from the material surface and thus no longer inhibits hydrogen absorption. Therefore a different approach was chosen for the experiments reported: Hydrogen absorption under UHV conditions at room temperature. After the usual activation process, the vanadium surface was cleaned by 5 keV Ar{sup +} ion bombardment. Thus oxygen absorption at the specimen surface (and new reactions with oxygen from the remaining gas) could be avoided, or removed. By means of thermal desorption mass spectrometry (TDMS), hydrogen absorption as a function of argon ion dose was analysed. TDMS measurements performed for specimens treated by ion bombardment prior to H{sup 2} exposure showed two H{sup 2} desorption peaks, in contrast to the profiles measured with specimens not exposed to ion bombardment. It is assumed that the ion bombardment disturbs the crystal structure so that further sites for hydrogen absorption are produced. (orig./CB) [Deutsch] Bei der Beladung von Vandium mit Wasserstoff wird ueblicherweise die Probe nach einer Aktivierungsprozedur bei 1 atm Wasserstoff auf Temperaturen im Bereich von 500 bis 600 C hochgeheizt und danach schrittweise abgekuehlt. In diesem Temperaturbereich nimmt die Wasserstoffloeslichkeit mit abnehmender Temperatur zu. Entscheidend fuer die Beladung ist aber auch die Tatsache, dass bei Temperaturen groesser 250 C Sauerstoff von der Oberflaeche desorbiert und dadurch die Absorption von Wasserstoff nicht mehr blockieren kann. Im Rahmen der hier beschriebenen Untersuchungen sollte die Wasserstoffbeladung unter UHV-Bedingungen bei

  20. Influence of ion bombardment on structure and properties of TiZrN thin film

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yu-Wei, E-mail: james722@itrc.narl.org.tw [Instrument Technology Research Center, National Applied Research Laboratories Taiwan (China); Huang, Jia-Hong; Yu, Ge-Ping [Department of Engineering and System Science, National Tsing Hua University, Taiwan (China); Hsiao, Chien-Nan; Chen, Fong-Zhi [Instrument Technology Research Center, National Applied Research Laboratories, Taiwan (China)

    2015-11-01

    Highlights: • (Ti,Zr)N thin films were produced using dual guns with Ti and Zr targets. • Ti{sub 0.5}Zr{sub 0.5}N shows excellent hardness of 37.8 GPa with exhibiting (1 1 1) preferred orientation. • Resistivity is inverse proportional to the packing density. • Hardness is proportional to the packing density. - Abstract: The study is focused on the characterization of TiZrN thin film by controlling the behavior of ion bombardment. Thin films are grown using radio frequency magnetron sputtering process on Si wafer. The negative bias voltage ranging from −20 V to −130 V was applied to the substrate. The ion current density increases rapidly as substrate bias is lower than −60 V, then slightly increases as the critical value about −60 V is exceeded. At the substrate bias of −60 V, the ion current density is close to 0.56 mA/cm{sup 2}. The resistivity measured by four-point probe decreases from conditions −20 V to −60 V and then increases for substrate bias increases from −60 V to −130 V. The resistivity of TiZrN films is contributed from the packing factor. The N/TiZr ratios about 1 were measured by Rutherford backscattering spectrometer, and the packing factors of TiZrN films can also be obtained by the results of RBS. Field Emission scanning electron microscope (FEG-SEM) is used to characterize the thickness and structure of the deposited TiZrN film. X-ray diffraction (XRD) is used to determine the preferred orientation and lattice parameter. The precursor results of XRD show that all the coating samples exhibited (1 1 1) preferred orientation, and the hardness values of TiZrN films were ranging from 20 to 40 GPa. To sum up the precursor studies, the TiZrN films which can improve the properties from TiN and ZrN is a new ceramic material with higher potential. Following the advance process and analysis research, the structure and properties can be correlated and as a reference for industry application.

  1. Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling

    Energy Technology Data Exchange (ETDEWEB)

    Schmalhorst, Jan; Reiss, Guenter; Hoenik, V. [Thin Films and Nanostructures, Department of Physics, Univ. Bielefeld (Germany); Weis, Tanja; Engel, Dieter; Ehresmann, Arno [Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology, Kassel Univ. (Germany)

    2007-07-01

    Artificial ferrimagnets (AFi) have many applications as, e.g., pinned reference electrodes in magnetic tunnel junctions. It is known that the application of ion bombardment induced magnetic patterning with He ions on a single layer reference electrode of magnetic tunnel junctions is possible. For some applications a combination of ion bombardment induced magnetic patterning and artificial ferrimagnets as a reference electrode is desirable. The effect of ion bombardment induced magnetic patterning on pinned artificial ferrimagnets with a Ru interlayer which is frequently used in magnetic tunnel junctions as well as pinned AFis with a Cu interlayer has been tested. Special attention has been given to the question whether the antiferromagnetic interlayer exchange coupling can withstand the ion dose necessary to turn the exchange bias.

  2. Modulation transfer function and detective quantum efficiency of electron bombarded charge coupled device detector for low energy electrons

    Czech Academy of Sciences Publication Activity Database

    Horáček, Miroslav

    2005-01-01

    Roč. 76, č. 9 (2005), 093704:1-6 ISSN 0034-6748 R&D Projects: GA ČR(CZ) GA202/03/1575 Keywords : electron bombarded CCD * modulation transfer function * detective quantum efficiency Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.235, year: 2005

  3. Ion bombardment induced damage in silicon carbide studied by ion beam analytical methods

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, E.; Kotai, E. [Magyar Tudomanyos Akademia, Budapest (HU). Research Inst. for Particle and Nuclear Physics (RIPNP); Khanh, N.Q.; Horvath, Z.E.; Lohner, T.; Battistig, G.; Zolnai, Z.; Gyulai, J. [Research Inst. for Technical Physics and Materials Science, Budapest (Hungary)

    2001-07-01

    Damage created by implantation of Al{sup +} ions into 4H-SiC is characterized using backscattering spectrometry in combination with channeling. The measurability of the damage profile in the carbon sublattice was demonstrated using the 4260 keV {sup 12}C({alpha},{alpha}){sup 12}C resonance. To create disorder, Al{sup +} ions with energy of 200 keV and 350 keV were implanted at room temperature. As an independent method, cross-sectional transmission electron microscopy was used to study the damage structure in irradiated 4H-SiC. (orig.)

  4. Low-energy ion bombardment of frozen bacterial spores and its relevance to interplanetary space

    International Nuclear Information System (INIS)

    Tuleta, M.; Gabla, L.; Szkarlat, A.

    2005-01-01

    The panspermia hypothesis is concerned with the dissemination of life in space in the form of simple micro-organisms. During an interplanetary journey the micro-organisms are subjected to the action of, among others, the solar wind. We have simulated experimentally such conditions bombarding frozen bacterial spores with low-energy hydrogen ions. On the basis of the results obtained and our earlier research, a new look at the panspermia hypothesis is discussed. The general conclusion is that unprotected naked spores, their conglomerates and protected spores can survive attack of the solar wind, although to various degrees. (authors)

  5. A theoretical approach to sputtering due to molecular ion bombardment, 1

    International Nuclear Information System (INIS)

    Karashima, Shosuke; Ootoshi, Tsukuru; Kamiyama, Masahide; Kim, Pil-Hyon; Namba, Susumu.

    1981-01-01

    A shock wave model is proposed to explain theoretically the non-linear effects in sputtering phenomena by molecular ion bombardments. In this theory the sputtering processes are separated into two parts; one is due to linear effects and another is due to non-linear effects. The treatment of the linear parts is based on the statistical model by Schwarz and Helms concerning a broad range of atomic collision cascades. The non-linear parts are treated by the model of shock wave due to overlapping cascades, and useful equations to calculate the sputtering yields and the dynamical quantities in the system are derived. (author)

  6. Low-energy ion bombardment of frozen bacterial spores and its relevance to interplanetary space

    Energy Technology Data Exchange (ETDEWEB)

    Tuleta, M.; Gabla, L. [Jagiellonian Univ., Institute of Physics, Cracow (Poland); Szkarlat, A. [Clinical Children' s Hospital of the Jagiellonian Univ., Medical College, Lab. of Microbiology, Cracow (Poland)

    2005-04-01

    The panspermia hypothesis is concerned with the dissemination of life in space in the form of simple micro-organisms. During an interplanetary journey the micro-organisms are subjected to the action of, among others, the solar wind. We have simulated experimentally such conditions bombarding frozen bacterial spores with low-energy hydrogen ions. On the basis of the results obtained and our earlier research, a new look at the panspermia hypothesis is discussed. The general conclusion is that unprotected naked spores, their conglomerates and protected spores can survive attack of the solar wind, although to various degrees. (authors)

  7. Push-and-stick mechanism for charged and excited small cluster emission under ion bombardment

    International Nuclear Information System (INIS)

    Bitensky, I.S.; Parilis, E.S.; Wojciechowski, I.A.

    1992-01-01

    The mechanism for the formation, excitation and ionization of small clusters emitted under ion bombardment is discussed. It is shown that the increased degree of ionization for the transition metal dimers, trimers and tetramers can be explained by the existence of an additional effective channel for their formation, namely the associative ionization process. A simple estimate shows that the sticking together of a fast cascade atom and the pushed out surface atom is 30-40 times more effective for dimer formation, than the recombination of two fast atoms. This push-and-stick mechanism of cluster formation could also be effective for the formation of trimers and tetramers. (orig.)

  8. A liquid-like model for the morphology evolution of ion bombarded thin films

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, L., E-mail: luca.repetto@unige.it [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Lo Savio, R. [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Šetina Batič, B. [Inštitut Za Kovinske Materiale in Tehnologije, Lepi pot 11, 1000 Ljubljana (Slovenia); Firpo, G.; Angeli, E.; Valbusa, U. [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2015-07-01

    Thin solid films exposed to ion irradiation exhibit a peculiar evolution that can differ substantially from what is observed for bulk samples. The phenomenology of the patterns that self-organize on the substrate is very rich, with morphologies that display several degrees of order upon the modification of initial film characteristics and irradiation parameters. This richness paves the way for the fabrication of novel functional surfaces, but it is also an indication of the complexity of the underlying driving mechanisms. A remarkable simplification for the comprehension of these phenomena can come from the noteworthy similarity of the obtained patterns with those showing up when liquids dewet from their substrates. Here, we analyze the possibility to apply a liquid-like model to explain the morphology evolution of ion bombarded thin films for the whole phenomenology showing up in experiments. In establishing this connection between liquids and ion bombarded thin films, we propose to use also for liquids the insight gained for our system with recent experiments that stress the importance of the substrate topography for the selection of the dewetting mechanism. If confirmed, this result would lead to a reconsideration of the importance of capillary waves in spinodal dewetting, and will help to understand the low reproducibility of the related experimental results.

  9. Conical surface textures formed by ion bombarding 2% Be-Cu alloy

    International Nuclear Information System (INIS)

    Panitz, J.K.G.

    1991-01-01

    A homogeneous, micrometer-sized conical surface texture forms on 2% Be-Cu alloy which is bombarded with an argon beam produced by a Kaufman ion source. The dimensions of the features that form depend strongly on argon energy (from 250 to 1500 eV); argon fluence (10 19 to 10 20 ions cm -2 ); and argon flux (0.1 to 1 mA cm -2 ). The texture morphology depends less strongly on the background ambient (Mo versus graphite), earlier alloy heat treatments and the temperature during bombardment (100 o C and 450 o C). As the texture matures with increasing fluence, the number of large features increases at the expense of the number of small features. The observed relationship between texture formation and ion flux suggests that the evolution of these features is not adequately described by theories predicting that the mature conical side-wall angle is related to the angle of the maximum sputtering yield. These textured surfaces can be coated with other metals for a variety of possible applications including pulsed power Li + beam anodes; cold cathode field emission devices; optical absorbers and catalysis supports. (author)

  10. Conical surface textures formed by ion bombarding 2% Be Cu alloy

    International Nuclear Information System (INIS)

    Panitz, J.K.G.

    1990-01-01

    A homogeneous, micrometer-sized conical surface texture forms on 2% Be-Cu alloy which is bombarded with an argon beam produced by a Kaufman ion source. The dimensions of the features that form strongly depend on: (1) argon energy (from 250 to 1500 eV), (2) fluence (10 19 to 10 20 ions/cm 2 ), and (3) flux (0.1 to 1 mA/cm 2 ). The texture morphology depends less strongly on the background ambient (Mo vs graphite), earlier alloy heat treatments and the temperature during bombardment (100 degree C and 450 degree C). As the texture matures with increasing fluence, the number of large features increases at the expense of the number of small features. The observed relationship between texture formation and ion flux suggests that the evolution of these features is not adequately described by theories predicting that the mature conical sidewall angle is related to the angle of the maximum sputtering yield. These textured surfaces can be coated with other metals for a variety of possible applications including: (1) pulsed power Li+ beam anodes, (2) cold cathode field emission devices, (3) optical absorbers and (4) catalysis supports. 18 refs., 5 figs

  11. Electron bombardment cross-linking of coating materials

    International Nuclear Information System (INIS)

    Mileo, J.-C.

    1976-01-01

    The use of medium-power electron accelerators to cure paints and varnishes and to make them insoluble is described by making a special analysis of the physico-chemical aspect of the process. The following points in particular are examined: the effect of radiation on matter; general aspects of radiochemical polymerization, and the application of radiation polymerization to varnish drying. A quick review is then made of problems linked to the choice of radiation and to the influence of the oxygen in air. An electron accelerator and a method of calorimetric dosimetery are described [fr

  12. Radiation from silver films bombarded by low-energy electrons

    International Nuclear Information System (INIS)

    Chung, M.S.; Callcott, T.A.; Kretschmann, E.; Arakawa, E.T.

    1980-01-01

    Emission spectra from Ag films irradiated by low energy electrons (20-1500 eV) have been measured, and the results compared with theory. For relatively smooth films, two peaks in the spectra are resolved. One at 3.73 eV, the volume plasmon energy, is attributed to transition radiation and/or bremsstrahlung. The second, at about 3.60 eV, is very sensitive to surface roughness in both position and magnitude and is produced by roughness-coupled radiation from surface plasmons. For rough films, the roughness-coupled radiation dominates the emission. In addition to spectral shapes, the polarization of the radiation and its intensity as a function of electron energy were measured. The experimental results are compared with new calculations of roughness-coupled emission which account for most of our observations. They indicate that high wavevector roughness components play the dominant role in the emission process. (orig.)

  13. Comments on Auger electron production by Ne/sup +/ bombardment of surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Pepper, S V; Ferrante, J [National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center

    1979-09-01

    In this letter, the authors first report rather conclusive experimental evidence showing that the Ne Auger signal is due to asymmetric Ne-metal collisions and not symmetric Ne-Ne collisions. Next it is shown that the Ne Auger signal is in fact observable by Ne/sup +/ bombardment of Si and with signal strength comparable to that of the Si Auger signal for 3 keV incident ion energy. Finally, they comment on some trends in the relative amplitudes of the 21.9 and 25.1 eV Ne Auger signals as a function of incident ion energy and target species.

  14. Thermohydraulic behavior of liquid metal pool submitted to electronic bombardment

    International Nuclear Information System (INIS)

    Brun, Patrice

    1998-01-01

    This thesis deals with the thermohydraulics of liquid metal molten by an electron beam. We study the relationship between the liquid metal pool and the vapor rate. The aim is to find good conditions increasing the metal vapor rate. In first place, energy losses are identified. Mains are convection (buoyancy and thermo-capillary) strengthen by the deformation of the molten pool. The first action is to reduce the liquid interface deformation with a transient spot realized by scanning the electron beam. I find that in this case, the optimum vapor rate is obtained when the crossing time of the beam is smaller than characteristic time of formation of the cavity, but greater than the heating time of the surface. Secondly, I impose forces to change the morphology of the flow. Two actions are tried: magnetic field application and rotating motion of the crucible. External magnetic field application may reduce convective flow, by the creation of a magnetic brake. But in my experiment, magnetic field deteriorates electron beam before to be effective. Results obtained by the rotating motion of the crucible approve this choice to reduce energy losses and increase vapor rate. This growth of vapor rate is due to an expansion of the emitted vapor source and an increase of the central temperature of the molten pool. Nevertheless with the increase of the rotation velocity and after the optimum vapor rate, I note that the flow is not axisymmetric. My observation give to think about instabilities that are developed by baroclinic waves. The comparison of my works with the Eady's linear theory gives good results. (author) [fr

  15. The influence of noble-gas ion bombardment on the electrical and optical properties of clean silicon surfaces

    International Nuclear Information System (INIS)

    Martens, J.W.D.

    1980-01-01

    A study of the effect of argon and helium ion bombardment on the electrical and optical properties of the clean silicon (211) surface is described. The objective of the study was to determine the effect of noble gas ions on the density of surface states at the clean silicon surface. (Auth.)

  16. Self-organised nano-structuring of thin oxide-films under swift heavy ion bombardment

    International Nuclear Information System (INIS)

    Bolse, Wolfgang

    2006-01-01

    Surface instabilities and the resulting self-organisation processes play an important role in nano-technology since they allow for large-array nano-structuring. We have recently found that the occurrence of such instabilities in thin film systems can be triggered by energetic ion bombardment and the subsequent self-assembly of the surface can be nicely controlled by fine-tuning of the irradiation conditions. The role of the ion in such processes is of double nature: If the instability is latently present already in the virgin sample, but self-assembly cannot take place because of kinetic barriers, the ion impact may just supply the necessary atomic mobility. On the other hand, the surface may become instable due to the ion beam induced material modifications and further irradiation then results in its reorganisation. In the present paper, we will review recently observed nano-scale self-organisation processes in thin oxide-films induced by the irradiation with swift heavy ions (SHI) at some MeV/amu energies. The first example is about SHI induced dewetting, which is driven by capillary forces already present in the as-deposited samples. The achieved dewetting pattern show an amazing similarity to those observed for liquid polymer films on Si, although in the present case the samples were kept at 80 K and hence have never reached their melting point. The second example is about self-organised lamellae formation driven by planar stresses, which are induced by SHI bombardment under grazing incidence and result in a surface instability and anisotropic plastic deformation (hammering effect). Taking advantage of these effects and modifying the irradiation procedure, we were able to generate more complex structures like NiO-'nano-towers' of 2 μm height and 200 nm in diameter

  17. Immediate fabrication of flower-like graphene oxide by ion beam bombardment

    International Nuclear Information System (INIS)

    Cheng, Junjie; Zhang, Yuanyuan; Zhang, Guilong; Xiong, Shiquan; Pei, Renjun; Cai, Dongqing; Wu, Zhengyan

    2015-01-01

    Graphical abstract: - Highlights: • Ion beam bombardment (IBB) could modify the microstructure of graphene oxide (GO). • IBB could transform a compact multi-layered GO to a few-layered flower-like GO. • IBB could effectively improve the dispersion and the related properties of GO. • The main mechanism was proposed to be the etching and charge effects of IBB. - Abstract: An effective and convenient method using ion beam bombardment (IBB) for separating a multi-layered compact graphene oxide (GO) piece into several small few-layered loose pieces was developed, and it was found that those small GO pieces had formed a flower-like structure. Therein, the main mechanism was proposed to be the etching and charge effects of IBB. This work could provide a facile and promising approach for improving the dispersion and the related properties of GO. Furthermore, X-ray diffraction and Raman spectrum determinations demonstrated that, with the increasing fluence, IBB could effectively decrease the chemical groups in the layers of GO, resulting in the decrease of the layer distance.

  18. Immediate fabrication of flower-like graphene oxide by ion beam bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Junjie [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Zhang, Yuanyuan; Zhang, Guilong [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Xiong, Shiquan [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Pei, Renjun, E-mail: rjpei2011@sinano.ac.cn [Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Cai, Dongqing, E-mail: dqcai@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Wu, Zhengyan, E-mail: zywu@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China)

    2015-12-01

    Graphical abstract: - Highlights: • Ion beam bombardment (IBB) could modify the microstructure of graphene oxide (GO). • IBB could transform a compact multi-layered GO to a few-layered flower-like GO. • IBB could effectively improve the dispersion and the related properties of GO. • The main mechanism was proposed to be the etching and charge effects of IBB. - Abstract: An effective and convenient method using ion beam bombardment (IBB) for separating a multi-layered compact graphene oxide (GO) piece into several small few-layered loose pieces was developed, and it was found that those small GO pieces had formed a flower-like structure. Therein, the main mechanism was proposed to be the etching and charge effects of IBB. This work could provide a facile and promising approach for improving the dispersion and the related properties of GO. Furthermore, X-ray diffraction and Raman spectrum determinations demonstrated that, with the increasing fluence, IBB could effectively decrease the chemical groups in the layers of GO, resulting in the decrease of the layer distance.

  19. Heavy-Ion-Induced Electronic Desorption of Gas from Metals

    CERN Document Server

    Molvik, A W; Mahner, E; Kireeff Covo, M; Bellachioma, M C; Bender, M; Bieniosek, F M; Hedlund, E; Krämer, A; Kwan, J; Malyshev, O B; Prost, L; Seidl, P A; Westenskow, G; Westerberg, L

    2007-01-01

    During heavy-ion operation in several particle accelerators worldwide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion-induced gas desorption scales with the electronic energy loss (dEe/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

  20. Light ions cyclotron bombardment to simulate fast neutron radiation damage in nuclear materials

    International Nuclear Information System (INIS)

    Segura, E.; Lucki, G.; Aguiar, D.

    1984-01-01

    The applicability and limitations of the use of cyclotron light ions bombardment to simulate the effects of the neutron irradiation are presented. Light ions with energies of about 10 MeV are capable to produce homogeneous damage in specimens suitable for measuring bulk mechanical properties although their low damage rate of 10 -5 dpa.sec -1 limit the dose range to a few dpa. On the other hand, cyclotron alpha particle implantation provides a fast and convenient way of introducing helium with a minimum of side effects so that we can take advantage of this technique to get better understanding of the mechanism by which this insoluble gas produces high temperature embrittlement. Some experimental details such as dimensions and cooling techniques are described. Finally a description of the infrastructure for cyclotron alpha particle implantation and a creep-test facility of the Division of Radiation Damage at IPEN-CNEN/SP are presented. (Author) [pt

  1. An ion accelerator facility for the preparation of nuclear bombardement targets

    International Nuclear Information System (INIS)

    Grime, G.W.; Takacs, J.

    1981-01-01

    As a result of the demand for increasingly complex nuclear bombardment targets in this laboratory, work has started on the construction of a medium-energy accelerator facility capable of preparing targets both by ion implantation and by heavy-ion sputtering. Basic consideration was given in the design to flexibility and simplicity. The ion source chosen was the Harwell sputter ion gun which is capable of producing ions of practically any element at currents up to several hundred μA. This was modified to suit our specific requirement. The acceleration system was constructed to operate at a maximum of 100 kV, and the beam is focussed by a three-cylinder electrostatic lens. The ions are analysed by 50 0 magnet which is capable of a mass dispersion of 7 mm in the target chamber between adjacent mass numbers at mass 100. A slit feedback system is used to stabilise the energy against short-term fluctuations. The system is fitted with two target chambers; one after the magnet and one after the electrostatic lens. The latter is used for applications such as sputtering. Two dimensional scanning is available in both target chambers for ensuring uniformity of implantation over areas larger than the spot size. Using this apparatus, implanted targets of 3 He and 20 Ne have been prepared. In addition high quality films of refractory metals have been sputtered using Ar or Xe beams. (orig.)

  2. Directional effect on coloration in LiF crystal by H{sup +} and H{sub 2}{sup +} ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Mingle, Gan; Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Jianer, Zeng; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    In the present paper, the first results are reported about the coloration in LiF crystals induced by bombardments of single hydrogen ions (H{sup +}) and molecular hydrogen ions (H{sub 2}{sup +}) with the same velocity under the <100> aligned and random conditions. For the single hydrogen ion irradiation, the coloration is rather simple. The F-type color center absorption under the <100> aligned condition becomes larger than that under the random condition with the dose increase because of larger fraction of electronic energy loss under channeling condition. On the contrary, the coloration for the molecular ions does not show big channeling effect. In the low dose region some difference can be seen but the difference of coloration is not observed any more with the dose increase. The pronounced coloration for molecular ions under the channeling condition is observed in comparison with that for single ions. (author)

  3. Ion-bombardment effects on the fatigue life of stainless steel under simulated fusion first-wall conditions

    International Nuclear Information System (INIS)

    Kohse, G.E.

    1983-02-01

    An experiment which uses the MITR-II 5 MW research reactor to simulate several aspects of the anticipated environment of a fusion reactor first wall is described. Pressurized tube specimens are subjected simultaneously to stress and temperature cycling, surface bombardment by energetic helium and lithium ions and bulk irradiation by high-energy neutrons. Analysis of the samples is aimed primarily at determining the behavior of the ion bombarded surface layer, which has a depth of 2.5 μm, with particular reference to possible effects on the fatigue life of the material

  4. Simulation study of secondary electron images in scanning ion microscopy

    CERN Document Server

    Ohya, K

    2003-01-01

    The target atomic number, Z sub 2 , dependence of secondary electron yield is simulated by applying a Monte Carlo code for 17 species of metals bombarded by Ga ions and electrons in order to study the contrast difference between scanning ion microscopes (SIM) and scanning electron microscopes (SEM). In addition to the remarkable reversal of the Z sub 2 dependence between the Ga ion and electron bombardment, a fine structure, which is correlated to the density of the conduction band electrons in the metal, is calculated for both. The brightness changes of the secondary electron images in SIM and SEM are simulated using Au and Al surfaces adjacent to each other. The results indicate that the image contrast in SIM is much more sensitive to the material species and is clearer than that for SEM. The origin of the difference between SIM and SEM comes from the difference in the lateral distribution of secondary electrons excited within the escape depth.

  5. Recovery of 201Tl by ion exchange chromatography from proton bombarded thallium cyclotron targets

    International Nuclear Information System (INIS)

    Walt, T.N. van der; Naidoo, C.

    2000-01-01

    A method based on ion exchange chromatography is presented for the recovery of 201 Tl and its precursor 201 Pb from proton bombarded natural thallium cyclotron targets. After bombardment the target is dissolved in diluted nitric acid. Water, hydrazine and ammonium acetate are added to the solution and the lead radioisotopes separated from the thallium by cation exchange chromatography on a Bio-Rex 70 column. The sorbed lead radioisotopes are eluted with dilute nitric acid and the separation repeated on a second Bio-Rex 70 column. After elution of the remaining thallium the column is left for 32 hours and the 201 Tl formed by decay of 201 Pb is eluted with an ammonium acetate solution. The 201 Tl eluate is acidified with a HNO 3 -HBr-Br 2 mixture and the resulting solution is passed through an AG MP-1 anion exchanger column to remove any remaining lead isotopes. The 201 Tl is eluted with a hydrazine solution, the eluate evaporated to dryness and the 201 Tl finally dissolved in an appropriate solution to produce a 201 TlCl solution suitable for medical use. A high quality 201 Tl product is obtained containing ≤ 0.1 μg of Tl/mCi (37 MBq) 201 Tl. The radionuclidic impurities are less than the maximum values specified by the US Pharmacopoeia and the British Pharmacopoeia. (orig.)

  6. Comparison of secondary ion emission induced in silicon oxide by MeV and KeV ion bombardment

    International Nuclear Information System (INIS)

    Allali, H.; Nsouli, B.; Thomas, J.P.; Szymczak, W.; Wittmaack, K.

    1993-09-01

    The surface and near-surface composition of SiO 2 layers, has been investigated by negative secondary ion emission mass spectrometry (SIMS) using MeV and KeV ion bombardment in combination with time-of-flight (TOF) mass analysis. The spectra recorded in the mass range 0-100 u are dominated by surface impurities, notably hydrocarbons and silicon polyanions incorporating H and OH entities. The characteristic (fragmentation) patterns are quite different for light and high-velocity ion impact. In high-velocity TOF-SIMS analysis of P-doped layers, prepared by chemical vapour deposition (CVD), the mass lines at 63 and 79 u are very prominent and appear to correlate with the phosphorus concentration (PO 2 and PO 3 , respectively). It is shown, however, that for unambiguous P analysis one has to use dynamic SIMS or high mass resolution. (author) 11 refs., 5 figs

  7. Surface damage studies of ETFE polymer bombarded with low energy Si ions (≤100 keV)

    International Nuclear Information System (INIS)

    Minamisawa, Renato Amaral; Almeida, Adelaide De; Budak, Satilmis; Abidzina, Volha; Ila, Daryush

    2007-01-01

    Surface studies of ethylenetetrafluoroethylene (ETFE), bombarded with Si in a high-energy tandem Pelletron accelerator, have recently been reported. Si ion bombardment with a few MeV to a few hundred keV energies was shown to be sufficient to produce damage on ETFE film. We report here the use of a low energy implanter with Si ion energies lower than 100 keV, to induce changes on ETFE films. In order to determine the radiation damage, ETFE bombarded films were simulated with SRIM software and analyzed with optical absorption photometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to show quantitatively the physical and chemical property changes. Carbonization occurs following higher dose implantation, and hydroperoxides were formed following dehydroflorination of the polymer

  8. Optical radiation emitted by a silver surface bombarded by low-energy electrons

    International Nuclear Information System (INIS)

    Miserey, F.; Lebon, P.; Septier, A.; Trehin, F.; Beaugrand, C.

    1975-01-01

    Thick silver targets are obtained on flat glass discs by evaporation in a UHV cell (p -10 torr) and their optical coefficients measured by ellipsometry. A field-emission electron gun bombards a limited region of the target, corresponding to the entry pupil of a light spectrometer. Radiation emitted in the domain 250-600nm is analyzed for both normal and parallel polarizations. Spectral distributions of photons are obtained by using a very sensitive counting device including a multi channel analyzer. First experimental results concerning optical radiation generated by 6keV electrons are reported and compared to Transition Radiation and Bremsstrahlung theoretical spectra [fr

  9. Energy dependence of angular distributions of sputtered particles by ion-beam bombardment at normal incidence

    International Nuclear Information System (INIS)

    Matsuda, Yoshinobu; Ueda, Yasutoshi; Uchino, Kiichiro; Muraoka, Katsunori; Maeda, Mitsuo; Akazaki, Masanori; Yamamura, Yasunori.

    1986-01-01

    The angular distributions of sputtered Fe-atoms were measured using the laser fluorescence technique during Ar-ion bombardment for energies of 0.6, 1, 2 and 3 keV at normal incidence. The measured cosine distribution at 0.6 keV progressively deviated to an over-cosine distribution at higher energies, and at 3 keV the angular distribution was an overcosine distribution of about 20 %. The experimental results agree qualitatively with calculations by a recent computer simulation code, ACAT. The results are explained by the competition between surface scattering and the effects of primary knock-on atoms, which tend to make the angular distributions over-cosine and under-cosine, respectively. (author)

  10. Dependence of ion - photon emission characteristics on the concentration of implanted atoms of the bombarding beam

    International Nuclear Information System (INIS)

    Belykh, S.F.; Evtukhov, R.N.; Redina, I.V.; Ferleger, V.Kh.

    1989-01-01

    Results of experiment, where Dy + beams, its spraying products emitting intensively optical radiation with continuous spectrum (CSR), are used for tantalum surface bombardment, are presented. The given experiment allowed one to separate the scattered particle CSR contribution and was conducted under controlled beam n atom concentration on the target surface. E 0 energy and j 0 dysprosium ion flux density made up respectively 3.5 keV and 3x10 5 Axcm -2 . The obtained result analysis has shown that a notable dependence of spectrum type on n value is detected. Dy scattered atoms to not emit CSR. The main contribution to CSR is made by sprayed particles, containing dysprosium atoms

  11. Damage structure in Nimonic PE16 alloy ion bombarded to high doses and gas levels

    International Nuclear Information System (INIS)

    Farrell, K.; Packan, N.H.

    1981-01-01

    The Nimonic PE16 alloy in solution-treated-and-aged condition was bombarded simultaneously with nickel ions and α and deuteron beams at 625 0 C to doses of 80 to 313 dpa at He/dpa = 10 and D/dpa = 25. Microstructural changes consisted of the introduction of dislocations and of cavities, and the redistribuion of γ' precipitates to these defects. Cavitational swelling remained below 1%. Cavities were represented by several distinct size classes, the smaller ones believed to be gas bubbles, and some larger ones associated with preferred growth of precipitate. Formation of bubbles at grain boundaries, and large cavities at incoherent twins intensified the possibility of mechanical separation of interfaces under high-gas irradiation conditions

  12. Study of clean and ion bombardment damaged silver single crystal surfaces by work function measurements

    International Nuclear Information System (INIS)

    Chelvayohan, N.

    1982-06-01

    Work function values of the (110), (100) and (111) faces of silver single crystal were measured by the photoelectric emission method and found to be 4.14 +- 0.04 eV, 4.22 +-0.04 eV and 4.46 +- 0.02 eV respectively. Oxygen adsorption on the faces were studied by surface potential measurement. Strong oxygen adsorption was observed on (110) and (100) faces, whereas the (111) face was found to be inert for oxygen adsorption. Oxygen adsorption on the (111) face damaged by argon ion bombardment was also investigated. The above results were compared with those of early reported work function and oxygen adsorption values. (U.K.)

  13. Silicon nanodot formation and self-ordering under bombardment with heavy Bi3 ions

    International Nuclear Information System (INIS)

    Boettger, Roman; Heinig, Karl-Heinz; Bischoff, Lothar; Liedke, Bartosz; Huebner, Rene; Pilz, Wolfgang

    2013-01-01

    Si nanodots of high density and hexagonal short-range order are observed upon normal-incidence bombardment of hot, crystalline Si with Bi 3 + ions having a kinetic energy of a few tens of keV. The heights of nanodots are comparable to their widths of ∝20 nm. The implanted Bi accumulates in tiny Bi nanocrystals in a thin Si top layer which is amorphous due to implantation damage. Light and heavy ions up to Xe cause smoothing of surfaces, but Bi 3 + ions considered here have a much higher mass. Atomistic simulations prove that each Bi 3 + impact deposits an extremely high energy density resulting in a several nanometer large melt pool, which resolidifies within a few hundreds of picoseconds. Experiments confirm that dot patterns form only if the deposited energy density exceeds the threshold for melting. Comparing monatomic and polyatomic Bi ion irradiation, Bi-Si phase separation and preferential ion erosion are ruled out as driving forces of pattern formation. A model based on capillary forces in the melt pool explains the pattern formation consistently. High-density Si nanodots are formed by polyatomic Bi ion irradiation of hot Si surfaces. Each impact causes local transient melt pools smaller than the dots. Hexagonally ordered patterns evolve by self-organization driven by repeated ion-induced melting of tiny volumes. Homogeneously distributed Bi nanocrystals are found in the a-Si film. These nanocrystals are related to particularities of the Si-Bi phase diagram. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Electron Beam Ion Sources

    CERN Document Server

    Zschornacka, G.; Thorn, A.

    2013-12-16

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

  15. Electron-ion collisions

    International Nuclear Information System (INIS)

    Crandall, D.H.

    1982-01-01

    This discussion concentrates on basic physics aspects of inelastic processes of excitation, ionization, and recombination that occur during electron-ion collisions. Except for cases of illustration along isoelectronic sequences, only multicharged (at least +2) ions will be specifically discussed with some emphasis of unique physics aspects associated with ionic charge. The material presented will be discussed from a primarily experimental viewpoint with most attention to electron-ion interacting beams experiments

  16. Treatment of PVC using an alternative low energy ion bombardment procedure

    Science.gov (United States)

    Rangel, Elidiane C.; dos Santos, Nazir M.; Bortoleto, José Roberto R.; Durrant, Steven F.; Schreiner, Wido H.; Honda, Roberto Y.; Rangel, Rita de Cássia C.; Cruz, Nilson C.

    2011-12-01

    In many applications, polymers have progressively substituted traditional materials such as ceramics, glasses, and metals. Nevertheless, the use of polymeric materials is still limited by their surface properties. Frequently, selective modifications are necessary to suit the surface to a given application. Amongst the most common treatments, plasma immersion ion implantation (PIII) has attracted the attention of many researchers owing to its versatility and practicality. This method, however, requires a power supply to provide high voltage (tens of kV) negative pulses, with a controlled duty cycle, width and frequency. Owing to this, the implementation of PIII on the industrial scale can become economically inviable. In this work, an alternative plasma treatment that enables low energy ion bombardment without the need of a high voltage pulse generator is presented. To evaluate the efficiency of the treatment of polymers, polyvinylchloride, PVC, specimens were exposed to 5 Pa argon plasmas for 3600 s, at excitation powers, P, of between 10 and 125 W. Through contact angle and atomic force microscopy data, the influence of P on the wettability, surface free energy and roughness of the samples was studied. Surface chemical composition was measured by X-ray photoelectron spectroscopy, XPS. To evaluate the effect of aging under atmospheric conditions, contact angle and XPS measurements were performed one and 1334 days after the treatment. The plasma potential and ion density around the driven electrode were determined from Langmuir probe measurements while the self-bias potential was derived with the aid of an oscilloscope. From these data it was possible to estimate the mean energy of ions bombarding the PVC surface. Chlorine, carbon and oxygen contamination were detected on the surface of the as-received PVC. Upon exposure to the plasma, the proportion of chlorine was observed to decrease while that of oxygen increased. Consequently, the wettability and surface energy

  17. Treatment of PVC using an alternative low energy ion bombardment procedure

    International Nuclear Information System (INIS)

    Rangel, Elidiane C.; Santos, Nazir M. dos; Bortoleto, José Roberto R.; Durrant, Steven F.; Schreiner, Wido H.; Honda, Roberto Y.; Cássia C Rangel, Rita de; Cruz, Nilson C.

    2011-01-01

    In many applications, polymers have progressively substituted traditional materials such as ceramics, glasses, and metals. Nevertheless, the use of polymeric materials is still limited by their surface properties. Frequently, selective modifications are necessary to suit the surface to a given application. Amongst the most common treatments, plasma immersion ion implantation (PIII) has attracted the attention of many researchers owing to its versatility and practicality. This method, however, requires a power supply to provide high voltage (tens of kV) negative pulses, with a controlled duty cycle, width and frequency. Owing to this, the implementation of PIII on the industrial scale can become economically inviable. In this work, an alternative plasma treatment that enables low energy ion bombardment without the need of a high voltage pulse generator is presented. To evaluate the efficiency of the treatment of polymers, polyvinylchloride, PVC, specimens were exposed to 5 Pa argon plasmas for 3600 s, at excitation powers, P, of between 10 and 125 W. Through contact angle and atomic force microscopy data, the influence of P on the wettability, surface free energy and roughness of the samples was studied. Surface chemical composition was measured by X-ray photoelectron spectroscopy, XPS. To evaluate the effect of aging under atmospheric conditions, contact angle and XPS measurements were performed one and 1334 days after the treatment. The plasma potential and ion density around the driven electrode were determined from Langmuir probe measurements while the self-bias potential was derived with the aid of an oscilloscope. From these data it was possible to estimate the mean energy of ions bombarding the PVC surface. Chlorine, carbon and oxygen contamination were detected on the surface of the as-received PVC. Upon exposure to the plasma, the proportion of chlorine was observed to decrease while that of oxygen increased. Consequently, the wettability and surface energy

  18. Exfoliation on stainless steel and inconel produced by 0.8-4 MeV helium ion bombardment

    International Nuclear Information System (INIS)

    Paszti, F.; Mezey, G.; Pogany, L.; Fried, M.; Manuaba, A.; Kotai, E.; Lohner, T.; Pocs, L.

    1982-11-01

    Trying to outline the energy dependence of surface deformations such as exfoliation and flaking on candidate CTR first-wall materials, stainless steel and two types of inconels were bombarded by 0.8, 1 and 4 MeV helium ions. All the bombarded spots could be characterized by by large exfoliations covering almost the total implanted area. No spontaneous rupture was observed except on one type of inconel where flaking took place right after reaching the critical dose. After mechanical opening of the formations, similar inner morphology was found as in our previous studies on gold. (author)

  19. EPR study of electron bombarded alkali- and alkaline-earth halide crystal surfaces

    Science.gov (United States)

    Fryburg, G. C.; Lad, R. A.

    1975-01-01

    An EPR study of electron bombarded LiF, NaCl, KCl, CaF2 and BaF2 polycrystalline surfaces has shown that small metal particles are formed on the surfaces of the crystals. Identification was made from CESR signals. The symmetric line-shape of the signals, even at 77 K, indicated that the particles were less than 0.5 micron in diameter. Signals due to F centers were observed in LiF but not in the other halides. Implications to metal deposition are considered.

  20. Chemical changes induced on a TiO2 surface by electron bombardment

    International Nuclear Information System (INIS)

    Vergara, L.I.; Passeggi, M.C.G.; Ferron, J.

    2007-01-01

    We study the TiO 2 (Ti 4+ ) chemical reduction induced by electron bombardment using Auger electron spectroscopy and factor analysis. We show that the electron irradiation of a TiO 2 sample is characterized by the appearance of a lower Ti oxidation state, Ti 2 O 3 (Ti 3+ ), followed by a further deposition of carbon, which is present inevitably in the environment even under ultra-high vacuum conditions. The appearance of C over the surface is found to be a complex mechanism which affects the reduction process through passivation of the electron-induced oxygen desorption and formation of titanium carbide. For very high irradiation doses, we also found that the chemical changes on the surface are stopped due to the deposition of carbon in a graphitic form

  1. Is low-energy-ion bombardment generated X-ray emission a secondary mutational source to ion-beam-induced genetic mutation?

    Energy Technology Data Exchange (ETDEWEB)

    Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Thopan, P.; Yaopromsiri, C. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► Detected X-ray emission from metal, plastic and biological samples. ► Characteristic X-ray emission was detected from metal but not from non-metals. ► Low-energy ion bombarded bacteria held in different sample holders. ► Bacteria held in metal holder had higher mutation rate than in plastic holder. ► Ion-beam-induced X-ray from biological sample is not a basic mutation source. -- Abstract: Low-energy ion beam biotechnology has achieved tremendous successes in inducing crop mutation and gene transfer. However, mechanisms involved in the related processes are not yet well understood. In ion-beam-induced mutation, ion-bombardment-produced X-ray has been proposed to be one of the secondary mutation sources, but the speculation has not yet been experimentally tested. We carried out this investigation to test whether the low-energy ion-beam-produced X-ray was a source of ion-beam-induced mutation. In the investigation, X-ray emission from 29-keV nitrogen- or argon- ion beam bombarded bacterial Escherichia coli (E. coli) cells held in a metal or plastic sample holder was in situ detected using a highly sensitive X-ray detector. The ion beam bombarded bacterial cells held in different material holders were observed for mutation induction. The results led to a conclusion that secondary X-ray emitted from ion-beam-bombarded biological living materials themselves was not a, or at least a negligible, mutational source, but the ion-beam-induced X-ray emission from the metal that made the sample holder could be a source of mutation.

  2. Is low-energy-ion bombardment generated X-ray emission a secondary mutational source to ion-beam-induced genetic mutation?

    International Nuclear Information System (INIS)

    Thongkumkoon, P.; Prakrajang, K.; Thopan, P.; Yaopromsiri, C.; Suwannakachorn, D.; Yu, L.D.

    2013-01-01

    Highlights: ► Detected X-ray emission from metal, plastic and biological samples. ► Characteristic X-ray emission was detected from metal but not from non-metals. ► Low-energy ion bombarded bacteria held in different sample holders. ► Bacteria held in metal holder had higher mutation rate than in plastic holder. ► Ion-beam-induced X-ray from biological sample is not a basic mutation source. -- Abstract: Low-energy ion beam biotechnology has achieved tremendous successes in inducing crop mutation and gene transfer. However, mechanisms involved in the related processes are not yet well understood. In ion-beam-induced mutation, ion-bombardment-produced X-ray has been proposed to be one of the secondary mutation sources, but the speculation has not yet been experimentally tested. We carried out this investigation to test whether the low-energy ion-beam-produced X-ray was a source of ion-beam-induced mutation. In the investigation, X-ray emission from 29-keV nitrogen- or argon- ion beam bombarded bacterial Escherichia coli (E. coli) cells held in a metal or plastic sample holder was in situ detected using a highly sensitive X-ray detector. The ion beam bombarded bacterial cells held in different material holders were observed for mutation induction. The results led to a conclusion that secondary X-ray emitted from ion-beam-bombarded biological living materials themselves was not a, or at least a negligible, mutational source, but the ion-beam-induced X-ray emission from the metal that made the sample holder could be a source of mutation

  3. Diamond-like carbon prepared by pulsed laser deposition with ion bombardment: physical properties

    Science.gov (United States)

    Písařík, P.; Mikšovský, J.; Remsa, J.; Zemek, J.; Tolde, Z.; Jelínek, M.

    2018-01-01

    Diamond-like carbon (DLC) and titanium-doped DLC thin films were prepared by unique hybrid system consisting of pulsed laser deposition, ion source (bombardment) and magnetron sputtering. The influence of deposition parameters (ion energies, deposition pressures and magnetron power) on composition and physical properties was studied. Composition and sp 3/ sp 2 ratio were determined by XPS. sp 3/ sp 2 ratio was in the range from 1.4 to 2.2 for undoped DLC and from 3.4 to 4.8 for Ti-DLC. AFM showed that the layers were smooth, but with small amounts of random droplets. The measurements of the contact angle and determination of surface free energy were made for water, diiodomethane and ethylene glycol. Hardness and reduced Young's modulus varied from 20 to 31 GPa and from 182 to 276 GPa, respectively. Film adhesion was determined by scratch test; L C3 reached 23 N for DLC and 27 N for TiDLC. Optimization of sp 3/ sp 2 ratio, hardness and adhesion to biomedical alloys will advance the DLC coatings usability in the field of implantology.

  4. L-subshell ionization studies of Au for α-particle and lithium-ion bombardment

    International Nuclear Information System (INIS)

    Dhal, B.B.; Nandi, T.; Padhi, H.C.; Trautmann, D.

    1995-01-01

    L-subshell ionization of Au has been investigated for α-particle and lithium-ion bombardments with energies 0.54-1.74 MeV u -1 and 0.65-1.44 MeV u -1 , respectively. Comparison of experimental x-ray production cross sections with the predictions of the ECPSSR and SCA theories shows reasonably good agreement for L α and L β x-rays, whereas for L γ and L γ1+5 the ECPSSR theory underestimates the cross sections by about 60% for both α-particle and lithium-ion impact, and the SCA theory agrees reasonably well. The ECPSSR theory underestimates the L 1 - and L 2 -subshell ionization cross sections and gives good agreement for the L 3 -subshell, whereas the SCA theory overestimates the L 3 -subshell ionization cross sections and gives good agreement for L 1 and L 2 . The experimental data for the total-ionization cross sections are within 25% of the predictions of both the theories. (Author)

  5. Ion-beam bombardment induced texture in nickel substrates for coated high-Tc superconductors

    International Nuclear Information System (INIS)

    Wang, S S; Wu, K; Zhou, Y; Godfrey, A; Meng, J; Liu, M L; Liu, Q; Liu, W; Han, Z

    2003-01-01

    Biaxially textured metal substrates are often used for making YBa 2 Cu 3 O 7-x coated conductors with high critical current density. Generally, specific rolling and high-temperature annealing procedures are required to obtain the biaxial texture for metal substrates. Here, we report on a new method for developing strongly biaxially textured grain structure in rolled nickel tape by argon ion-beam bombardment. X-ray diffraction (XRD) θ-2θ scans have shown that a (200) diffraction peak intensity of the Ni foil processed by ion-beam structure modification (ISM) is two orders of magnitude greater than that of cold-rolled foil, while the (111) and (220) intensities are very weak. In the ISM processed Ni foils, from the rocking curve, the full width at half maximum (FWHM) value of the (200) peak has been found to be less than 5.9 deg., whilst the in-plane FWHM obtained from a pole figure analysis is just 8 deg. We discuss the possible mechanisms leading to the texture changes during ISM. (rapid communication)

  6. Modulation transfer function and detective quantum efficiency of electron bombarded charge coupled device detector for low energy electrons

    International Nuclear Information System (INIS)

    Horacek, Miroslav

    2005-01-01

    The use of a thinned back-side illuminated charge coupled device chip as two-dimensional sensor working in direct electron bombarded mode at optimum energy of the incident signal electrons is demonstrated and the measurements of the modulation transfer function (MTF) and detective quantum efficiency (DQE) are described. The MTF was measured for energy of electrons 4 keV using an edge projection method and a stripe projection method. The decrease of the MTF for a maximum spatial frequency of 20.8 cycles/mm, corresponding to the pixel size 24x24 μm, is 0.75≅-2.5 dB, and it is approximately the same for both horizontal and vertical directions. DQE was measured using an empty image and the mixing factor method. Empty images were acquired for energies of electrons from 2 to 5 keV and for various doses, ranging from nearly dark image to a nearly saturated one. DQE increases with increasing energy of bombarded electrons and reaches 0.92 for electron energy of 5 keV. For this energy the detector will be used for the angle- and energy-selective detection of signal electrons in the scanning low energy electron microscope

  7. Low-energy ion bombardment to tailor the interfacial and mechanical properties of polycrystalline 3C-silicon carbide

    International Nuclear Information System (INIS)

    Liu Fang; Li, Carolina H.; Pisano, Albert P.; Carraro, Carlo; Maboudian, Roya

    2010-01-01

    Low-energy Ar + ion bombardment of polycrystalline 3C-silicon carbide (poly-SiC) films is found to be a promising surface modification method to tailor the mechanical and interfacial properties of poly-SiC. The film average stress decreases as the ion energy and the bombardment time increase. Furthermore, this treatment is found to change the strain gradient of the films from positive to negative values. The observed changes in stress and strain gradient are explained by ion peening and thermal spikes models. In addition, the poly-SiC films show a significant enhancement in corrosion resistance by this treatment, which is attributed to a reduction in surface energy and to an increase in the compressive stress in the near-surface region.

  8. Changes in phase composition and stress state of surface layers of VK20 hard alloy after ion bombardment

    International Nuclear Information System (INIS)

    Platonov, G.L.; Leonov, E.Yu.; Anikin, V.N.; Anikeev, A.I.

    1988-01-01

    Titanium ion bombardment of the surface of the hard VK20 alloy is studied for its effect on variations in the phase and chemical composition of its surface layers. It is stated that ion treatment results in the appearance of the η-phase of Co 6 W 6 C composition in the surface layer of the VK20 alloy, in the increase of distortions and decrease of coherent scattering blocks of the hard alloy carbide phase. Such a bombardment is found to provoke a transition of the plane-stressed state of the hard alloy surface into the volume-stressed state. It is established that ion treatment does not cause an allotropic transition of the cobalt phase α-modification, formed during grinding of the hard alloy, into the β-modification

  9. Ion bombardment and adsorption studies on ilmenite (FeTiO3) by X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Schulze, P.D.

    1983-01-01

    The effects of 5 KeV argon and oxygen ion bombardment on FeTiO3 (ilmenite) at low temperatures have been studied using x-ray photoelectron spectroscopy (XPS). Also, using this same technique, the adsorption of O 2 , NO, N 2 O, and CO at 300 K and the adsorption of O 2 and D 2 O at 150K have been studied. Argon and oxygen ion bombardment of ilmenite have confirmed earlier studies on metal oxides that argon ions generally reduce the anion species while oxygen ions generally oxidize the anion species. The two iron states involved were Fe sup +2 and Fe sup O. The reduction of Ti sup +4 was not verified although a significant shift in the Ti(2p1,3) binding energies toward the metallic state was observed after oxygen ion bombardment at low temperatures. At temperatures above 150K, O 2 adsorbs dissociatively on ilmenite while D 2 O adsorbs molecularly below 170K. Above 300 K NO, N 2 O, and CO do not appear to adsorb dissociatively. Low temperature adsorption of D 2 O was found to be inhibited by predosing the ilmenite with O 2

  10. Ion bombardment and adsorption studies on ilmenite (FeTiO3) by X-ray photoelectron spectroscopy

    Science.gov (United States)

    Schulze, P. D.

    1983-01-01

    The effects of 5 KeV argon and oxygen ion bombardment on FeTiO3 (ilmenite) at low temperatures have been studied using X-ray photoelectron spectroscopy (XPS). Also, using this same technique, the adsorption of O2, NO, N2O, and CO at 300 K and the adsorption of O2 and D2O at 150K have been studied. Argon and oxygen ion bombardment of ilmenite have confirmed earlier studies on metal oxides that argon ions generally reduce the anion species while oxygen ions generally oxidize the anion species. The two iron states involved were Fe sup +2 and Fe sup O. The reduction of Ti sup +4 was not verified although a significant shift in the Ti(2p1,3) binding energies toward the metallic state was observed after oxygen ion bombardment at low temperatures. At temperatures above 150K, O2 adsorbs dissociatively on ilmenite while D2O adsorbs molecularly below 170K. Above 300 K No, N2O, and CO do not appear to adsorb dissociatively. Low temperature adsorption of D2O was found to be inhibited by predosing the ilmenite with O2.

  11. Systematic analysis of neutron yields from thick targets bombarded by heavy ions and protons with moving source model

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Takashi; Kurosawa, Tadahiro; Nakamura, Takashi E-mail: nakamura@cyric.tohoku.ac.jp

    2002-03-21

    A simple phenomenological analysis using the moving source model has been performed on the neutron energy spectra produced by bombarding thick targets with high energy heavy ions which have been systematically measured at the Heavy-Ion Medical Accelerator (HIMAC) facility (located in Chiba, Japan) of the National Institute of Radiological Sciences (NIRS). For the bombardment of both heavy ions and protons in the energy region of 100-500 MeV per nucleon, the moving source model incorporating the knock-on process could be generally successful in reproducing the measured neutron spectra within a factor of two margin of accuracy. This phenomenological analytical equation is expressed having several parameters as functions of atomic number Z{sub p}, mass number A{sub p}, energy per nucleon E{sub p} for projectile, and atomic number Z{sub T}, mass number A{sub T} for target. By inputting these basic data for projectile and target into this equation we can easily estimate the secondary neutron energy spectra at an emission angle of 0-90 deg. for bombardment with heavy ions and protons in the aforementioned energy region. This method will be quite useful to estimate the neutron source term in the neutron shielding design of high energy proton and heavy ion accelerators.

  12. Secondary ion yield changes in Si and GaAs due to topography changes during O+2 or Cs+ ion bombardment

    International Nuclear Information System (INIS)

    Stevie, F.A.; Kahora, P.M.; Simons, D.S.; Chi, P.

    1988-01-01

    Changes in secondary ion yields of matrix and dopant species have been correlated with changes in surface topography during O + 2 bombardment of Si and GaAs. In Si, profiles were measured in (100) wafers at 6- and 8-keV impact energy. At 6 keV, a yield increase of about 70% occurred for Si + over a depth range of 2.5 to 3.5 μm, with changes in other species ranging from a decrease of ∼20% for Si + 3 to an increase of more than 25% for O + . The development of a rippled surface topography was observed in scanning electron micrographs over the same depth range. Similar effects occurred over a 3--5 μm depth range for 8-keV ions, and in (111) silicon at a depth of 3 to 4 μm for 6-keV ions. No differences were noted between p- and n-type silicon, or implanted and unimplanted silicon. In GaAs, profiles were measured in (100) wafers at 2.5-, 5.5-, and 8-keV impact energies. At 8 keV, a yield increase of about 70% was found for GaO + in the range 0.6--1.0 μm, with smaller changes for other matrix species. At 5.5 keV, similar effects were observed, but over a depth interval of 0.3 to 0.7 μm. No yield changes were detected at 2.5-keV impact energy. The yield changes at the higher energies were again correlated with the onset of changes in topography. No change in ion yield or surface topography was noted for Cs + bombardment of Si or GaAs. The topography and ion yield changes are affected by the angle of incidence and, for Si, the oxygen coverage. The results show that the practice of normalizing secondary ion mass spectrometry dopant profiles to a matrix signal must be modified for situations where matrix yield changes occur

  13. Electronic excitation effects on secondary ion emission in highly charged ion-solid interaction

    International Nuclear Information System (INIS)

    Sekioka, T.; Terasawa, M.; Mitamura, T.; Stoeckli, M.P.; Lehnert, U.; Fehrenbach, C.

    2001-01-01

    In order to investigate the secondary ion emission from the surface of conductive materials bombarded by highly charged heavy ions, we have done two types of experiments. First, we have measured the yield of the sputtered ions from the surface of solid targets of conductive materials (Al, Si, Ni, Cu) bombarded by Xe q+ (q=15-44) at 300 keV (v p =0.30 a.u) and at 1.0 MeV (v p =0.54 a.u). In view of the secondary ion yields as a function of the potential energy of the projectile, the increase rates below q=35, where the potential energy amounts to 25.5 keV, were rather moderate and showed a prominent increase above q=35. These phenomena were rather strong in the case of the metal targets. Second, we have measured the energy dependence of the yield of the sputtered ions from the surface of solid targets of conductive materials (C, Al) bombarded by Xe q+ (q=30,36,44) between 76 keV (v p =0.15 a.u) and 6.0 MeV (v p =1.3 a.u). A broad enhancement of the secondary ion yield has been found for Al target bombarded by Xe 44+ . From these experimental results, the electronic excitation effects in conductive materials for impact of slow highly charged heavy ions bearing high potential energy is discussed

  14. Ejection of fast recoil atoms from solids under ion bombardment (medium-energy ion scattering by solid surfaces: Pt. 3)

    International Nuclear Information System (INIS)

    Dodonoy, A.I.; Mashkova, E.S.; Molchanov, V.A.

    1989-01-01

    This paper is the third part of our review surface scattering. Part I, which was devoted to the scattering of ions by the surfaces of disordered solids, was published in 1972; Part II, concerning scattering by crystal surfaces, was published in 1974. Since the publication of these reviews the material contained in them has become obsolete in many respects. A more recent account of the status of the problem has been given in a number of studies, including the book by E.S. Mashkova and V.A. Molchanov, Medium-Energy Ion Scattering by Solid Surfaces (Atomizdat, Moscow, 1980), than extended version of which was published by North-Holland in 1985. We note, however, that at the time these reviews were written the study of fast recoil atoms had not been carried out systematically; the problem was studied only as a by-product of surface scattering and sputtering. For this reason, in the above-mentioned works and in other reviews the data relating to recoil atoms were considered only occasionally. In recent years there have appeared a number of works - theoretical, experimental and computer -specially devoted to the study of the ejection of recoil atoms under ion bombardment. A number of interesting effects, which are due to the crystal structure of the target, have been discovered. It therefore, appeared desirable to us to systematize the available material and to present it as Part III of our continuing review. (author)

  15. Ion induced high energy electron emission from copper

    Energy Technology Data Exchange (ETDEWEB)

    Ruano, G. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)], E-mail: gdruano@ceride.gov.ar; Ferron, J. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina); Departamento de Ingenieria de Materiales, Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)

    2008-11-15

    We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He{sup +}, Ne{sup +} and Ar{sup +}) and Li{sup +} ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

  16. Influence of keV-He ion bombardment on the magnetic properties of Co/Pd multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Mueglich, Nicolas; Buhl, Oliver; Weis, Tanja; Engel, Dieter; Ehresmann, Arno [Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel (Germany); Hellwig, Olav [San Jose Research Center, HGST, A Western Digital Company, CA (United States)

    2013-07-01

    Thin films of ferromagnetic Co separated by Pd films with thicknesses in the first ferromagnetic maximum of interlayer exchange coupling are magnetically dominated by perpendicular-to-plane anisotropy and labyrinth stripe domain patterns in remanence. During the magnetization reversal of such a multilayer system domain nucleation and domain wall movement can be observed for different external magnetic fields H. The influence of keV-He ion bombardment on the microstructure of the system and its resultant decrease of magnetic anisotropy has been investigated by vibrating sample magnetometry, polar magneto-optical Kerr effect and magnetic force microscopy. It is shown that areas of ferromagnetic in-plane anisotropy are created due to the ion bombardement and that the system shows an increasing quotient of superparamagnetism in the deeper layers of the multilayersystem.

  17. Temperature effect on the formation of a relief of diamond-like carbon coatings and its modification by ion bombardment

    International Nuclear Information System (INIS)

    Rubshtein, A.P.; Trakhtenberg, I.Sh.; Yugov, V.A.; Vladimirov, A.B.; Plotnikov, S.A.; Ponosov, Yu.S

    2006-01-01

    Using the method of pulsed arc sputtering of a graphite target the diamond-like coatings (DLC) ∼1.5 μm thick are deposited on a steel R6M5 substrate. The relief of the coatings obtained under various temperature conditions is investigated. Variations of carbon DLC surfaces are followed after their bombardment with accelerated argon or chemically active oxygen ions. Argon ion bombardment is established to be preferred for producing a smoothed-out DLC relief. It is shown that a DLC relief should be taken into account when measuring microhardness. It is recommended that transformation of interatomic bonds in irradiated subsurface layers be taken into consideration if information index of methods applied constitutes several monolayers [ru

  18. Diamond-like carbon layers modified by ion bombardment during growth and researched by Resonant Ultrasound Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Kocourek, Tomáš; Jelínek, Miroslav; Písařík, Petr; Remsa, Jan; Janovská, Michaela; Landa, Michal; Zemek, Josef; Havránek, Vladimír

    2017-01-01

    Roč. 417, Sep (2017), s. 213-217 ISSN 0169-4332 R&D Projects: GA ČR(CZ) GA15-05864S Institutional support: RVO:68378271 ; RVO:61388998 ; RVO:61389005 Keywords : in-situ ion bombardment * pulsed laser deposition * diamond-like carbon * hybrid technology * flm modification Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.387, year: 2016

  19. Anomalous time-of-flight distributions observed for argon implanted in silicon and resputtered by Ar+-ion bombardment

    International Nuclear Information System (INIS)

    van Veen, G.N.A.; Sanders, F.H.M.; Dieleman, J.; van Veen, A.; Oostra, D.J.; de Vries, A.E.

    1986-01-01

    A Si substrate is bombarded by 3-keV Ar + ions. From time-of-flight spectra of resputtered Ar neutrals at various target temperatures, we conclude that Ar-bubble formation takes place in the amorphized-Si top layer. The bubbles form and open during etching. The average kinetic energy of the Ar atoms is in agreement with the calculated average potential energy of the Ar atoms inside the bubbles

  20. The change of corrosion resistance of metals after bombardment by inert gas ions

    International Nuclear Information System (INIS)

    Vasil'ev, M.A.; Panarin, V.E.; Kosyachkov, A.A.

    2002-01-01

    Work functions of electrons and secondary ions of iron and oxygen from the surface of pure iron specimens pre-irradiated by argon ions were studied experimentally. One made use of the determined dependences in the experiments to passivate surface of low-carbon steel using the BULAT type commercial facilities. The designed extra device for those facilities ensured the required irradiation doses (equal to 10 17 atom x cm -2 ) resulting in improvement of steel corrosion resistance by several times [ru

  1. Study of the machining of uranium carbide rods obtained by continuous casting under electronic bombardment

    International Nuclear Information System (INIS)

    Rousset, P.; Accary, A.

    1965-01-01

    The authors consider the various methods of machining uranium mono-carbide and compare them critically in the case of their application to uranium carbide obtained by fusion under an electronic bombardment and continuous casting. This study leads them to propose two mechanical machining methods: cylindrical rectification and center-less rectification, preceded by a preliminary roughing out of a cylinder, the latter appearing more suitable. A study of the machining yields as a function of the diameter of the rough bars and of the diameter of the finished rods has shown that an optimum value of the rough bar diameter exists for each value of the finished rod diameter. It is found that the yield increases as the diameter itself increases, this yield rising from 45 per cent to around 70 per cent as the diameter of the rough bars increases from 25-26 mm to 37-38 mm. (authors) [fr

  2. Electrical conductivity of polytetrafluoroethylene in dc and ac electric fields under continuous electron bombardment

    International Nuclear Information System (INIS)

    Khatipov, S.A.; Turdybekov, K.M.; Milinchuk, V.K.

    1993-01-01

    A study has been made of the time of the radiation current density in dc and ac (10 2 -5-10 3 Hz) electric fields (10 3 -5-10 5 V/cm) at temperatures from 80 to 393 K and dose rates from 5-10 3 Gy/sec, for PTFE films (50-180 μm) with various thermal prehistories, when exposed to continuous bombardment by 9-MeV electrons. It has been shown that the experimental results cannot be interpreted from the standpoint of free-charge conduction; they can be explained qualitatively within the framework of concepts of inhomogeneous ionization of the substance, due to the formation of short tracks

  3. Photon counting imaging and centroiding with an electron-bombarded CCD using single molecule localisation software

    International Nuclear Information System (INIS)

    Hirvonen, Liisa M.; Barber, Matthew J.; Suhling, Klaus

    2016-01-01

    Photon event centroiding in photon counting imaging and single-molecule localisation in super-resolution fluorescence microscopy share many traits. Although photon event centroiding has traditionally been performed with simple single-iteration algorithms, we recently reported that iterative fitting algorithms originally developed for single-molecule localisation fluorescence microscopy work very well when applied to centroiding photon events imaged with an MCP-intensified CMOS camera. Here, we have applied these algorithms for centroiding of photon events from an electron-bombarded CCD (EBCCD). We find that centroiding algorithms based on iterative fitting of the photon events yield excellent results and allow fitting of overlapping photon events, a feature not reported before and an important aspect to facilitate an increased count rate and shorter acquisition times.

  4. Ion peening and stress relaxation induced by low-energy atom bombardment of covalent solids

    International Nuclear Information System (INIS)

    Koster, Monika; Urbassek, Herbert M.

    2001-01-01

    Using molecular-dynamics simulation, we study the buildup and relaxation of stress induced by low-energy (≤150 eV) atom bombardment of a target material. The effect is brought out most clearly by using an initially compressed specimen. As target material, we employ Si, based on the Tersoff potential. By varying the bond strength in the potential, we can specifically study its effect on damage production and stress changes. We find that in general, stress is relaxed by the atom bombardment; only for low bombarding energies and strong bonds, atom bombardment increases stress. We rationalize this behavior by considering the role of energized atoms and of recoil-implanted target atoms

  5. Intravenous coronary angiography utilizing K-emission and bremsstrahlung X-rays produced by electron bombardment

    International Nuclear Information System (INIS)

    1992-01-01

    The screening of the general population for coronary artery disease would be practical if a method existed for visualizing the extent of occlusion after an intravenous injection of contrast agent. Measurements performed with synchrotron radiation at SSRL and NSLS have shown that such an intravenous angiography procedure would be possible with an intense source of monochromatic X-rays. Because of the high cost of an electron synchrotron, theoretical analysis and experiments using inanimate phantoms has been undertaken to demonstrate the feasibility of using the spectrum produced by two appropriately chosen anode materials when bombarded with electrons in the 100--500 keV energy range for angiography. By using the X-rays emitted at 120 degree to the incident electron direction, about 20--30% of the X-ray intensity would be due to K-emission lines. Calculations using the TIGERP Monte Carlo Code, have shown that high quality angiograms of human coronary arteries should be possible with a contrast agent containing ytterbium, if an electron beam pulses of 16 kJ were used for each anode target. The experimental program supported in part by the DOE has consisted of these theoretical calculations and experiments at the Dynamitron Electron Accelerator Facility at BNL

  6. Electronic and Optical Properties of Aluminum Oxide Before and After Surface Reduction by Ar+ Bombardment

    Directory of Open Access Journals (Sweden)

    D. Tahir

    2014-08-01

    Full Text Available The electronic and optical properties of a-Al2O3 after induced by 3-keV Ar+ sputtering have been studied quantitatively by use of reflection electron energy loss spectroscopy (REELS spectra. The band gap values of a-Al2O3 was determined from the onset values of the energy loss spectrum to the background level of REELS spectra as a function of time Ar+ bombardment. The bandgap changes from 8.4 eV before sputtering to 6.2 eV after 4 minutes of sputtering.The optical properties of α-Al2O3 thin films have been determined by comparing the experimental cross section obtained from reflection electron energy loss spectroscopy with the theoretical inelastic scattering cross section, deduced from the simulated energy loss function (ELF by using QUEELS-ε(k-REELS software. The peak assignments are based on ELF and compared with reported data on the electronic structure of α-Al2O3 obtained using different techniques. The results demonstrate that the electronic and optical properties before and after surface reduction will provide further understanding in the fundamental properties of α-Al2O3 which will be useful in the design, modeling and analysis of devices applications performance.

  7. Charge-state correlated cross sections for the production of low-velocity highly charged Ne ions by heavy-ion bombardment

    International Nuclear Information System (INIS)

    Gray, T.J.; Cocke, C.L.; Justiniano, E.

    1980-01-01

    We report measured cross sections for the collisional production of highly charged low-velocity Ne recoil ions resulting from the bombardment of a thin Ne gas target by highly charged 1-MeV/amu C, N, O, and F projectiles. The measurements were made using time-of-flight techniques which allowed the simultaneous identification of the final charge state of both the low-velocity recoil ion and the high-velocity projectile for each collision event. For a given incident-projectile charge state, the recoil charge-state distribution is very dependent upon the final charge state of the projectile. Single- and double-electron capture events by incident bare nuclei and projectile K-shell ionization during the collision cause large shifts in the recoil charge-state distributions toward higher charge states. A previously proposed energy-deposition model is modified to include the effects of projectile charge-changing collisions during the collision for bare and hydrogenlike projectiles and is used to discuss the present experimental results

  8. Study of the electronic structure of pure aluminium, aluminium oxide and nitride by spectroscopy of electrons excited under electronic and photonic bombardment (X and UV)

    International Nuclear Information System (INIS)

    Gautier-Soyer, Martine

    1985-01-01

    This research thesis reports the use of electron spectroscopy with electrons excited under electronic or photonic (X or UV) bombardment for the study of electronic state density of aluminium, aluminium oxide (Al 2 O 3 ) and aluminium nitride (AlN). The objective is to get an insight into phenomena related to technological problems of adherence, wear, lubrication, corrosion or breakdown met in metals, insulators and semiconductors. The author highlighted the presence of occupied surface states on Al(111) and Al(100), and electronic levels localised in the forbidden band of Al 2 O 3 and AlN, induced by structural defects which promote surface reactivity [fr

  9. L-subshell ionization studies in Au and Bi for 19F and 28Si large-ion bombardment

    International Nuclear Information System (INIS)

    Padhi, H.C.; Dhal, B.B.; Nanal, V.; Prasad, K.G.; Tandon, P.N.; Trautmann, D.

    1996-01-01

    L x-ray production and subshell ionization cross sections of Au and Bi have been measured for the bombardment of 19 F and 28 Si ions in the energy range 30 endash 57 MeV and 36 endash 84 MeV, respectively. Comparison of the Lα x-ray production cross sections of Au with the earlier data by Malhi and Gray [Phys. Rev. A 44, 7199 (1991)] shows reasonable agreement for 19 F impact and their data are consistently higher for 28 Si at all energies. The measured Lα line energy shows a shift towards higher energy, which appears to be proportional to the square of the projectile atomic number at all impact energies. This shift suggests the presence of multiple ionization in the L and M shells with a simultaneous production of four M holes in Au at the impact energy of 3 MeVu -1 of 28 Si. The L-subshell ionization cross sections obtained from the measured x-ray production cross sections have been compared with the semiclassical approximation and perturbed stationary state theory with energy loss, Coulomb deflection, and relativistic correction for the electron motion calculations, which show large deviations for the L 1 subshell. The L 2 - and L 3 -subshell ionization cross sections are underestimated by both the theories by a factor of 1.2 endash 4.0 for 28 Si impact whereas for the 19 F case there is reasonable agreement for the L 3 cross section but the L 2 cross section is underestimated by 20 endash 30%. copyright 1996 The American Physical Society

  10. Physico-chemical and mechanical modifications of polyethylene and polypropylene by ion implantation, micro-wave plasma, electron beam radiation and gamma ray irradiation; Modifications physico-chimiques et mecaniques du polyethylene et du polypropylene par implantation ionique, plasma micro-ondes, bombardement d`electrons et irradiation gamma

    Energy Technology Data Exchange (ETDEWEB)

    Liao, J D

    1995-03-29

    A polyolefin surface becomes wettable when treated by micro-wave plasma or low-dose nitrogen ion implantation. A short time argon plasma treatment is sufficient to obtain polarizable peroxides on a polyolefin. X-ray photoelectron spectroscopy analyses, paramagnetic electronic resonance analyses, peroxides decomposition, wettability measurements and infrared active spectra analyses have shown that oxidized structures obtained from different treatment techniques play an important role in the interpretation of surface chemical properties of the polymer. Micro-wave plasma treatment, and in particular argon plasma treatment, yields more polarizable groups than ion implantation and is interesting for grafting. Hardness and elasticity modulus, measured by nano-indentation on a polyolefin, increase with an appropriate ion implantation dose. A 1.4 x 10{sup 17} ions.cm{sup -2} dose can multiply by 15 the hardness of high molecular weight polyethylene, and by 7 the elasticity modulus for a 30 nm depth. The viscous-plastic to quasi-elastic transition is shown. The thickness of the modified layer is over 300 nm. The study of friction between a metal sphere and a polyethylene cupula shows that ion implantation in the polymer creates a reticulated hard and elastic layer which improves its mechanical properties and reduces the erosion rate. Surface treatments on polymers used as biomaterials allow to adapt the surface properties to specific applications. 107 refs., 66 figs., 19 tabs., 4 annexes.

  11. Improvement of the wear resistance of electroplated Au-Ni coatings by Zr ion bombardment of Ni-B sublayer

    International Nuclear Information System (INIS)

    Lyazgin, Alexander; Shugurov, Artur; Sergeev, Viktor; Neufeld, Vasily; Panin, Alexey; Shesterikov, Evgeny

    2015-01-01

    The effect of bombardment of the Ni-B sublayer by Zr ion beams on the surface morphology and tribomechanical properties of Au-Ni coatings was investigated. It was found that the treatment has no significant effect on the surface roughness and grain size of the Au-Ni coatings, while it provides essential reducing of their friction coefficient and improvement of wear resistance. It is shown that increased wear resistance of these coatings was caused by their strain hardening resulted from localization of plastic strain. The optimal Zr fluence were determined that provide the maximum reduction of linear wear of the coatings

  12. Nano-scale pattern formation on the surface of HgCdTe produced by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A.B.; Gudymenko, A.I.; Kladko, V.P.; Korchevyi, A.A.; Savkina, R.K.; Sizov, F.F.; Udovitska, R.S. [V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kiev (Ukraine)

    2015-08-15

    Presented in this work are the results concerning formation of nano-scale patterns on the surface of a ternary compound Hg{sub 1-x}Cd{sub x}Te (x ∝ 0.223). Modification of this ternary chalcogenide semiconductor compound was performed using the method of oblique-incidence ion bombardment with silver ions, which was followed by low-temperature treatment. The energy and dose of implanted ions were 140 keV and 4.8 x 10{sup 13} cm{sup -2}, respectively. Atomic force microscopy methods were used for the surface topography characterization. The structural properties of MCT-based structure was analyzed using double and triple crystal X-ray diffraction to monitor the disorder and strain of the implanted region as a function of processing conditions. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Contribution to the study of point defects formed in nickel by electron bombardment

    International Nuclear Information System (INIS)

    Oddou, J.L.

    1968-12-01

    After a short account of the experimental techniques employed in our studies, the experimental results obtained on pure nickel samples are exposed. The apparition of the successive annihilation stages of point defects created by electron bombardment is established by isochronal heat treatments: the annihilation kinetics and the corresponding activation energies are determined. The effect of the incident particle doses is also studied. The experimental results are then compared with R.A. Johnson's theoretical calculations of the stability and the migration of point defects in nickel, and taking into account the results obtained by Peretto in magnetic after effect measurements. This leads us to a model in good agreement with calculations and experiment for the first stages. In a second chapter the behaviour of nickel doped by certain impurities is studied. First, the results concerning the rate of increase of resistivity (function of sample purity) is investigated. Two possible explanations of the observed phenomenon are proposed: either a deviation with respect to Mathiessen's law, or an increase of the number of defects formed in the presence of impurity atoms. Finally, a study of the resistivity recovery of the doped samples permits us to suggest an order of magnitude for the binding energy interstitial/impurity atom in the nickel matrix. (author) [fr

  14. Study of the point defects formed in cobalt by electron bombardment

    International Nuclear Information System (INIS)

    Sulpice, G.

    1968-12-01

    A study of the point defects formed in cobalt by electron bombardment is presented. The results are compared with those previously obtained for two other ferromagnetic metals of different structure, iron and nickel. In the first part we give a review of the literature concerning the creation of point defects, their contribution to resistivity and their annihilation mode in the three structure types. We then describe the experimental techniques adapted, in particular the study of the resistivity increase during a linear temperature rise. Our investigations concern the following, essential points : the observation of the successive annihilation stages of the point defects formed in pure cobalt, a study of the variations with respect to the doses and energy of the incident particles, and the determination of the annealing kinetics and the corresponding activation energies. The results are finally compared with the various models of point defect annihilation proposed for other metals: none of these interpretations is in perfect agreement with our results. In the case of cobalt we are thus led to modify the model proposed by our laboratory for iron an nickel. The difference between these three metals is explained by the anisotropic character of the cobalt matrix. (author) [fr

  15. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multi-dimensional Boolean valued functions in three dimensional lattice space. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion. The third topic is the formation of ripple structures on ion bombarded semiconductor surfaces treated in the first topic as the prepatterned substrate of the metallic deposition. This intriguing phenomenon has been known since the 1960's and various theoretical approaches have been explored. These previous models are discussed and a new non-linear model is formulated, based on the local atomic flow and associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important and it is shown that in this case, certain 'magic' angles can occur at which the ripple patterns are most clearly defined. The results including some analytic solutions of the nonlinear equation of motions are in very good agreement with experimental observation.

  16. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multi-dimensional Boolean valued functions in three dimensional lattice space. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion. The third topic is the formation of ripple structures on ion bombarded semiconductor surfaces treated in the first topic as the prepatterned substrate of the metallic deposition. This intriguing phenomenon has been known since the 1960's and various theoretical approaches have been explored. These previous models are discussed and a new non-linear model is formulated, based on the local atomic flow and associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important and it is shown that in this case, certain 'magic' angles can occur at which the ripple patterns are most clearly defined. The results including some analytic solutions of the nonlinear equation of motions are in very good agreement with experimental observation.

  17. Moessbauer of phase separation in FeNi multilayers under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, L.; Paesano, A.; Brueckman, M.E. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Scorzelli, R.B.; Dominguez, A.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Shinjo, T.; Ono, T.; Hosoito, N. [Kyoto Univ. (Japan). Inst. for Chemical Research

    1997-01-01

    We investigated the effect of noble gas irradiation (He, Ne, Ar and Xe) on the Fe-Ni multilayers with a very thin modulation and nominal composition in the invar region Fe{sub 0.63} Ni{sub 0.37}. The evaluation of the formation/stability of the Fe-Ni phases formed under irradiation with different ions and doses was followed by conversion electron Moessbauer spectroscopy (CEMS). (author). 21 refs., 4 figs., 2 tabs.; e-mail: scorza at novell.cat.cbpf.br.

  18. Polymerization of solid C60 under C60 cluster ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vacík, Jiří; Naramoto, H.; Narumi, K.

    2009-01-01

    Roč. 95, - (2009), s. 867-873 ISSN 0947-8396 R&D Projects: GA AV ČR(CZ) KAN400480701; GA MŠk(CZ) LC06041 Institutional research plan: CEZ:AV0Z10480505 Keywords : fulleren * cluster * bombardment * polymerization Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.595, year: 2009 http://www.springerlink.com/content/0947-8396

  19. Charge generation and trapping in bisphenol-A-polycarbonate/N-isopropylcarbazole mixture: A study by electron bombardment-induced conductivity

    International Nuclear Information System (INIS)

    Santos, S.; Caraballo, D.

    2007-01-01

    Electron bombardment-induced conductivity measurements were carried out on cast films of N-isopropylcarbazole (NIPC) dispersed into an amorphous matrix of bisphenol-A-polycarbonate. The charge generation was studied by estimating the hole yield (g), the fraction of charge escaping recombination, as a function of electric field and concentration of NIPC at room temperature. The hole yield, besides increasing by increasing the content of NIPC, was observed to increase with the electric field in the manner predicted by the Onsager theory of geminate recombination. Deep trapping levels were studied by filling under electron bombardment and observing transients. The deep traps were neutral in nature with a concentration on the order of 8.0x10 14 cm -3 , which was low enough not to degrade transport under normal conditions

  20. Enhancement of sp3 hybridized C in amorphous carbon films by Ar ion bombardment and Si incorporation

    International Nuclear Information System (INIS)

    Jung, Hae-Suk; Park, Hyung-Ho; Mendieta, I.R.; Smith, D.A.

    2003-01-01

    We report an effective method of increasing the sp 3 hybridization fraction in sputtered amorphous carbon (a-C) film by the combination of Ar ion bombardment and Si incorporation. In the deposition of an a-C film, Ar ion bombardment by controlling the applied bias voltage plays a role in creating high stress in film and causes the local bonding configuration to change to a sp 3 hybridized bond. Simultaneously, the incorporated Si in an a-C network breaks the sp 2 hybridized bonded ring and promotes the formation of a sp 3 hybridized bond. This enhancement of the sp 3 hybridized bonding characteristic is maximized for an a-C film with 23 at. % of Si and 100-150 V of applied bias voltage. In this region, the increase of resistivity, optical band gap, and mechanical hardness of a-C is attributed to the reduction of the sp 2 hybridized bonded ring and increased fraction of the sp 3 hybridized bond. However, at a higher bias voltage above 150 V, the enhancement effect is reduced due to the resputtering and thermally activated reconversion of a sp 3 to a sp 2 hybridized bond

  1. Study of the point defects formed in cobalt by electron bombardment; Etude des defauts ponctuels crees par bombardement electronique dans le cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Sulpice, G [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1968-12-01

    A study of the point defects formed in cobalt by electron bombardment is presented. The results are compared with those previously obtained for two other ferromagnetic metals of different structure, iron and nickel. In the first part we give a review of the literature concerning the creation of point defects, their contribution to resistivity and their annihilation mode in the three structure types. We then describe the experimental techniques adapted, in particular the study of the resistivity increase during a linear temperature rise. Our investigations concern the following, essential points : the observation of the successive annihilation stages of the point defects formed in pure cobalt, a study of the variations with respect to the doses and energy of the incident particles, and the determination of the annealing kinetics and the corresponding activation energies. The results are finally compared with the various models of point defect annihilation proposed for other metals: none of these interpretations is in perfect agreement with our results. In the case of cobalt we are thus led to modify the model proposed by our laboratory for iron an nickel. The difference between these three metals is explained by the anisotropic character of the cobalt matrix. (author) [French] Nous presentons une etude des defauts ponctuels crees par bombardement electronique dans le cobalt et comparons nos resultats a ceux obtenus precedemment dans deux autres metaux ferromagnetiques de structure differente, le fer et le nickel. Dans une premiere partie nous faisons une mise au point bibliographique comparee sur la creation des defauts, leur contribution a la resistivite et leur mode d'annihilation dans les trois types de structure. Nous decrivons ensuite les techniques experimentales mises au point, en particulier l'etude du revenu de la resistivite au cours d'une montee lineaire de temperature. Au cours de ce travail, nous avons mis en evidence les stades successifs d

  2. Contribution to the study of point defects formed in nickel by electron bombardment; Contribution a l'etude des defauts ponctuels crees par bombardement electronique dans le nickel

    Energy Technology Data Exchange (ETDEWEB)

    Oddou, J L [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1968-12-01

    After a short account of the experimental techniques employed in our studies, the experimental results obtained on pure nickel samples are exposed. The apparition of the successive annihilation stages of point defects created by electron bombardment is established by isochronal heat treatments: the annihilation kinetics and the corresponding activation energies are determined. The effect of the incident particle doses is also studied. The experimental results are then compared with R.A. Johnson's theoretical calculations of the stability and the migration of point defects in nickel, and taking into account the results obtained by Peretto in magnetic after effect measurements. This leads us to a model in good agreement with calculations and experiment for the first stages. In a second chapter the behaviour of nickel doped by certain impurities is studied. First, the results concerning the rate of increase of resistivity (function of sample purity) is investigated. Two possible explanations of the observed phenomenon are proposed: either a deviation with respect to Mathiessen's law, or an increase of the number of defects formed in the presence of impurity atoms. Finally, a study of the resistivity recovery of the doped samples permits us to suggest an order of magnitude for the binding energy interstitial/impurity atom in the nickel matrix. (author) [French] Apres avoir brievement rappele les techniques experimentales que nous avons utilisees pour cette etude, nous exposons les resultats experimentaux obtenus sur des echantillons de nickel pur. Les stades successifs d'annihilation des defauts ponctuels crees par bombardement electronique sont mis en evidence par traitements thermiques isochrones; les cinetiques de disparition, et les energies d'activation correspondantes sont determinees. Nous etudions egalement l'effet de la dose des particules incidentes. Les resultats experimentaux sont ensuite compares avec les calculs theoriques de R.A JOHNSON sur la stabilite

  3. Properties of TiN coatings deposited by the method of condensation with ion bombardment accompanied by high-energy ion beam

    International Nuclear Information System (INIS)

    Obrezkov, O.I.; Vershok, B.A.; Dormashev, A.B.; Margulev, I.Ya.; Molchanova, S.A.; Andreev, E.S.; Dervuk, V.V.

    2002-01-01

    Vacuum-sputtering adapted commercial facility based coating of stainless steel with titanium nitride followed two procedures: ion bombardment condensation (IBC) and IBC under simultaneous effect of ion beam (IB). The deposition rate was equal to 0.1 μm min -1 ; the investigated coatings were characterized by 2.5 μm depth. Comparison analysis of features and characteristics of the specimens, as well as, full-scale tests of a coated cutting tool enabled to make conclusions about advantages of application of IB assisted IBC technology in contrast to the reference IBC technology [ru

  4. Influence of both ion bombardment and chemical treatment processes on the electrical conductivity of PVC/poly aniline composites

    International Nuclear Information System (INIS)

    Gad, E.A.M.; Ashour, A.H.; Abdel-Hamid, H.M.; Sayed, W.M.

    1999-01-01

    In this article the changes in the electrical conductivity of PVC/poly aniline composites, as temperature consecutively increases, have been measured. The measurement were taken with correspondence to a control series of the composites under two processes:A. Composite samples bombarded with Ar + ions with fluence 2.44 x 10 13 beam ions /cm 2 ., sec 4 of 4 ke V beam energy where argon atoms can induce defects in the surface layer take place. Composite samples treated chemically with concentrated H 2 SO 4 as dopant which reacts with nitrogen atom in aniline. The measurements were also, done with the composites as the ratio of poly(aniline) stepped upward

  5. X-ray diffraction study of stress relaxation in cubic boron nitride films grown with simultaneous medium-energy ion bombardment

    International Nuclear Information System (INIS)

    Abendroth, B.; Gago, R.; Eichhorn, F.; Moeller, W.

    2004-01-01

    Relaxation of the intrinsic stress of cubic boron nitride (cBN) thin films has been studied by x-ray diffraction (XRD) using synchrotron light. The stress relaxation has been attained by simultaneous medium-energy ion bombardment (2-10 keV) during magnetron sputter deposition, and was confirmed macroscopically by substrate curvature measurements. In order to investigate the stress-release mechanisms, XRD measurements were performed in in-plane and out-of-plane geometry. The analysis shows a pronounced biaxial state of compressive stress in the cBN films grown without medium-energy ion bombardment. This stress is partially released during the medium-energy ion bombardment. It is suggested that the main path for stress relaxation is the elimination of strain within the cBN grains due to annealing of interstitials

  6. Influence of helium-ion bombardment on the surface properties of pure and ammonia-adsorbed water thin films

    International Nuclear Information System (INIS)

    Kondo, M.; Shibata, T.; Kawanowa, H.; Gotoh, Y.; Souda, R.

    2005-01-01

    The influence of the ion bombardment on the surface properties of water-ice films has been investigated. The films are irradiated with 1.5 keV He + ions and analyzed sequentially on the basis of time-of-flight secondary-ion mass spectrometry (TOF-SIMS). In order to minimize any temperature-induced effects, the measurements were made at 15 K. The damage of the films, as estimated from the H/D exchange between NH 3 and the D 2 O ice and the intermixing of NH 3 with the H 2 18 O ice, is recognized at the fluence above 2 x 10 14 ions/cm 2 . The sputtering yield of the D 2 O ice is determined as 0.9 ± 0.2 molecules per incoming He + ion. The temperature-programmed TOF-SIMS analysis of the water-ice films has been completed within the fluence of 5.8 x 10 12 ions/cm 2 , so that no appreciable damage of the film should be induced during the measurement

  7. Cornell electron beam ion source

    International Nuclear Information System (INIS)

    Kostroun, V.O.; Ghanbari, E.; Beebe, E.N.; Janson, S.W.

    1981-01-01

    An electron beam ion source (EBIS) for the production of low energy, multiply charged ion beams to be used in atomic physics experiments has been designed and constructed. An external high perveance electron gun is used to launch the electron beam into a conventional solenoid. Novel features of the design include a distributed sputter ion pump to create the ultrahigh vacuum environment in the ionization region of the source and microprocessor control of the axial trap voltage supplies

  8. Energy and dose characteristics of ion bombardment during pulsed laser deposition of thin films under pulsed electric field

    International Nuclear Information System (INIS)

    Fominski, V.Yu.; Nevolin, V.N.; Smurov, I.

    2004-01-01

    Experiments on pulsed laser deposition of Fe films on Si substrates were performed with the aim to analyze the role of factors determining the formation of an energy spectrum and a dose of ions bombarding the film in strong pulsed electric fields. The amplitude of the high-voltage pulse (-40 kV) applied to the substrate and the laser fluence at the Fe target were fixed during the deposition. Owing to the high laser fluence (8 J/cm 2 ) at a relatively low power (20 mJ), the ionization of the laser plume was high, but the Fe vapor pressure near the substrate was low enough to avoid arcing. Electric signals from a target exposed to laser radiation were measured under different conditions (at different delay times) of application of electric pulses. The Si(100) substrates were analyzed using Rutherford ion backscattering/channeling spectrometry. The ion implantation dose occurred to be the highest if the high-voltage pulse was applied at a moment of time when the ion component of the plume approached the substrate. In this case, the implanted ions had the highest energy determined by the amplitude of the electric pulse. An advance or delay in applying a high-voltage pulse caused the ion dose and energy to decrease. A physical model incorporating three possible modes of ion implantation was proposed for the interpretation of the experimental results. If a laser plume was formed in the external field, ions were accelerated from the front of the dense plasma, and the ion current depended on the gas-dynamic expansion of the plume. The application of a high-voltage pulse, at the instant when the front approached the substrate, maintained the mode that was characteristic of the traditional plasma immersion ion implantation, and the ion current was governed by the dynamics of the plasma sheath in the substrate-to-target gap. In the case of an extremely late application of a high-voltage pulse, ions retained in the entire volume of the experimental chamber (as a result of the

  9. Secondary emission of negative ions and electrons resulting from electronic sputtering of cesium salts

    International Nuclear Information System (INIS)

    Allali, H.; Nsouli, B.; Thomas, J.P.

    1993-04-01

    Secondary ion emission of negative ions and electrons from alkali salts bombarded with high energy (9 MeV) Ar +++ is discussed. Quite different features are observed according to the nature of the salt investigated (halide or oxygenated). In the case of cesium, the electron emission from halides is characterized by intense electron showers (several hundred electrons) with narrow distributions in intensity and orientation. Conversely, for oxygenated salts, these distributions are broader, much less intense (one order of magnitude), and the ion emission exhibits an dissymmetry, which has never been observed for inorganics. This last result is interpreted in terms of radiolysis of the oxygenated salt, a process well documented for gamma-ray irradiation, but not yet reported in secondary ion emission. (author) 17 refs.; 10 figs

  10. Electron-positron pair creation in heavy ion collisions

    International Nuclear Information System (INIS)

    Kienle, P.

    1987-01-01

    The authors review the status of experiments to study the electron positron pair creation in heavy ion atom collisions at bombarding energies close to the Coulomb barrier. The disentanglement and characterization of various sources of positrons observed in such collisions are described with a focus on the monoenergetic electron positron pairs observed. They seem to originate from the two-body decay of a family of neutral particles with masses of about 3m and lifetimes in the range of 6 x 10 - 14 s, produced by high Coulomb fields. First attempts were made to create these particles by resonant Bhabha scattering

  11. Electron bombardment fusion and continuous casting of uranium carbide. Fundamental study of the metallurgical and thermal processes

    International Nuclear Information System (INIS)

    Trouve, J.

    1968-02-01

    During a pilot production run, about 1.200 kg of uranium carbide cylindrical rods were prepared by electron bombardment fusion and continuous casting in an apparatus making it possible to operate in a constant vacuum automatically. In order to make the most of the fusion technique used, it was necessary to resolve a certain number of problems involved in this production. It was found that the energy yield for the electron bombardment heating using accelerating voltages of about 10 kV was 100 per cent; about 40 per cent of the electrons are re-emitted by back-scattering. These electrons leave the surface with practically zero energy. The fusion technique leads to the elimination of the majority of the metallic impurities. In order to explain the variations in the non-metallic impurity contents the different reactions occurring in the molten uranium monocarbide have been determined. A micrographic study of the rods obtained has shown various types of crystallization depending on the rate of casting and, despite the uniaxial symmetry of the cooling, no texture has been observed, whatever the rate of fusion employed. The aspects of the fracture surfaces observed on certain rods can be explained by theory in the domain where the material is elastic. Furthermore it has been shown that a decrease in the brittleness occurs as a result of the formation of fine precipitates of the Wiedmanstatten structure type. (authors) [fr

  12. Secondary emission from a CuBe target due to bombardment with parent and fragment ions of ammonia and phosphine

    International Nuclear Information System (INIS)

    Maerk, T.D.

    1977-01-01

    The secondary electron emission of the first dynode of a CuBe alloy sixteen dynode electron multiplier has been studied in the course of electron impact ionization studies of ammonia and phosphine. Relative secondary electron emission coefficients have been obtained for the singly and doubly charged parent and fragment ions of ammonia, ammonia-d 3 , phosphine and phosphine-d 3 for kinetic energies of 5,25 and 10,5 keV. It has been found, that in general deuterated ions have smaller γ coefficients, that ammonia ions have larger γ coefficients than corresponding phosphine ions, and that the γ coefficients increase with the complexity of the ion under study. (Auth.)

  13. Influence of substrate pre-treatments by Xe{sup +} ion bombardment and plasma nitriding on the behavior of TiN coatings deposited by plasma reactive sputtering on 100Cr6 steel

    Energy Technology Data Exchange (ETDEWEB)

    Vales, S., E-mail: sandra.vales@usp.br [Universidade de São Paulo (USP), Escola de Engenharia de São Carlos, Av. Trabalhador São Carlense 400, São Carlos, SP CEP 13566-590 (Brazil); Brito, P., E-mail: ppbrito@gmail.com [Pontifícia Universidade Católica de Minas Gerais (PUC-MG), Av. Dom José Gaspar 500, 30535-901 Belo Horizonte, MG (Brazil); Pineda, F.A.G., E-mail: pipe8219@gmail.com [Universidade de São Paulo (USP), Escola de Engenharia de São Carlos, Av. Trabalhador São Carlense 400, São Carlos, SP CEP 13566-590 (Brazil); Ochoa, E.A., E-mail: abigail_ochoa@hotmail.com [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); Droppa, R., E-mail: roosevelt.droppa@ufabc.edu.br [Universidade Federal do ABC (UFABC), Av. dos Estados, 5001, Santo André, SP CEP 09210-580 (Brazil); Garcia, J., E-mail: jose.garcia@sandvik.com [Sandvik Coromant R& D, Lerkrogsvägen 19, SE-12680, Stockholm (Sweden); Morales, M., E-mail: monieriz@gmail.com [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); Alvarez, F., E-mail: alvarez@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); and others

    2016-07-01

    In this paper the influence of pre-treating a 100Cr6 steel surface by Xe{sup +} ion bombardment and plasma nitriding at low temperature (380 °C) on the roughness, wear resistance and residual stresses of thin TiN coatings deposited by reactive IBAD was investigated. The Xe{sup +} ion bombardment was carried out using a 1.0 keV kinetic energy by a broad ion beam assistance deposition (IBAD, Kaufman cell). The results showed that in the studied experimental conditions the ion bombardment intensifies nitrogen diffusion by creating lattice imperfections, stress, and increasing roughness. In case of the combined pre-treatment with Xe{sup +} ion bombardment and subsequent plasma nitriding, the samples evolved relatively high average roughness and the wear volume increased in comparison to the substrates exposed to only nitriding or ion bombardment. - Highlights: • Effect of Xe ion bombardment and plasma nitriding on TiN coatings was investigated. • Xe ion bombardment with 1.0 KeV increases nitrogen retention in plasma nitriding. • 1.0 KeV ion impact energy causes sputtering, thus increasing surface roughness. • TiN coating wear is minimum after plasma nitriding due to lowest roughness.

  14. Radiation-induced segregation in light-ion bombarded Ni-8% Si

    International Nuclear Information System (INIS)

    Packan, N.H.; Heatherly, L.; Kesternich, W.; Schroeder, H.

    1986-01-01

    Tensile specimens 60 μm thick of Ni-8 at. % Si have been bombarded at 475 0 C to doses of 0.1 to 0.3 dpa with either 7 MeV proton or 28 MeV alpha particle beams. Deliberate embrittlement by high temperature (700 0 C) preimplantation of helium was required to produce intergranular fracture. Depth profile sputtering and analysis in a Scanning Auger Microprobe was then used to study radiation-induced segregation of silicon both at the external surfaces and at internal interfaces. The external surfaces exhibited a strongly silicon-enriched zone for the first 10 to 20 nm followed by a broad (approx.200 nm), shallow silicon-depleted region. Segregation of silicon to grain boundaries varied from interface to interface and possibly from region to region on a given interface. In general, however, depth profiles of silicon content with distance from internal boundaries showed no noticeable depletion zone and a more gradual fall-off compared to the profiles from external surfaces. The variations of RIS among boundaries and with type of interface probably reflect, at least in part, intrinsic differences in sink efficiency

  15. M-subshell ionization of U by light-ion bombardment

    International Nuclear Information System (INIS)

    Jesus, A.P.; Ribeiro, J.P.

    1988-01-01

    M X-rays of U were produced by proton, deuteron and alpha-particle bombardment in the energy range of 0.20-1.00 MeV/u. N 6.7 →M 5 ((M subα)),N 6 →M 4 (M β ), N 5 →M 3 (M γ ), N 4 →M 2 and N 2 →M 1 line yields were obtained from a least-squares fit to the spectra and used to convert M X-ray production into M-subshell ionization cross sections. The uncertainty induced by the atomic parameters (X-ray fluorescence yields, Coster-Kronig and radiative transition rates) used in the conversion is discussed. The subshell ionization cross sections are then compared to PWBA values corrected for Coulomb deflection and energy loss according to Brandt and Lapicki, to the semiclassical theoretical values of Kocbach and to relativistic PWBA results, corrected for Coulomb and binding effects, of Chen et al. Intrashell transitions induced by the projectile and multiple ionization are suggested as causes of disagreement between theory and experiment, especially for alpha-particles. It is concluded that theory must go beyond the simple picture of the first-order pertubation approximation to explain M-subshell results and the care must be taken in the choice of wave functions. (author) [pt

  16. Measurements of secondary neutrons producted from thick targets bombarded by heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kurosawa, T.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Nakao, N.; Shibata, T.; Uwamino, Y.; Nakanishi, N.; Fukumura, A.; Kumamoto, Y.

    1997-03-01

    We measured neutron angular and energy distributions from high energy heavy ions stopping in targets of carbon, aluminum, copper and lead at HIMAC. These spectra are much harder for the lighter target nucleus like carbon. This means that the momentum transfer in the forward direction from heavy ion beam to lighter nuclei is much higher than that to heavier nuclei. (author)

  17. MD simulation of atomic displacements in metals and metallic bilayers under low energy ion bombardment at 300 K

    International Nuclear Information System (INIS)

    Kornich, G.V.; Betz, G.; Bazhin, A.I.

    1999-01-01

    MD simulations of 100 eV Ar ion bombardment of (1 0 0) Ni and Al as well as Al/Ni bilayer crystals at 300 K have been performed and compared to previous calculations at 0 K. The Al/Ni bilayer crystal consisted of one Al layer on a (1 0 0) Ni substrate. Sputtering yields for Ni and Al/Ni show no temperature dependence, while for Al a pronounced increase with temperature was observed. The contributions of different mechanisms to the production of surface and bulk defects are discussed. The mean square displacement (MSD) of atoms is in all cases larger at 300 K as compared to 0 K. The larger MSD at 300 K is mainly due to an increase in lateral (perpendicular to the ion beam) motion of displaced atoms. Similar the number of atomic jumps, in which an atom leaves its original Wigner-Seitz cell, increases in all cases with temperature. For the pure elements the production of bulk vacancies and interstitials decreases with temperature, but the number of surface vacancies and ad-atoms increases with temperature. For the bilayer system practically no temperature dependence for defects was observed

  18. On the defect structure due to low energy ion bombardment of graphite

    Science.gov (United States)

    Marton, D.; Bu, H.; Boyd, K. J.; Todorov, S. S.; Al-Bayati, A. H.; Rabalais, J. W.

    1995-03-01

    Graphite surfaces cleaved perpendicular to the c axis have been irradiated with low doses of Ar + ions at 50 eV kinetic energy and perpendicular incidence. Scanning tunneling micrographs (STM) of these irradiated surfaces exhibited dome-like features as well as point defects. These dome-like features retain undisturbed graphite periodicity. This finding is attributed to the stopping of ions between the first and second graphite sheets. The possibility of doping semiconductors at extremely shallow depths is raised.

  19. Short-range order in InSb amorphized under ion bombardment

    International Nuclear Information System (INIS)

    Pavlov, P.V.; Tetel'baum, D.I.; Gerasimov, A.I.

    1979-01-01

    The investigation of short-range order is carried out in polycrystal InSb films, irradiated with Ne + ions with E=150 keV and with the 2x10 15 ion/cm 2 dose. The data are obtained testifying to the film amorphization, the cause of which is the defect storage but not the local melting. Stability of the obtained amorphous phase at the room temperature is noted

  20. Electron bombardment fusion and continuous casting of uranium carbide. Fundamental study of the metallurgical and thermal processes; Fusion sous bombardement d'electrons et coulee continue de carbure d'uranium. Etude fondamentale des processus metallurgiques et thermiques

    Energy Technology Data Exchange (ETDEWEB)

    Trouve, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-02-01

    During a pilot production run, about 1.200 kg of uranium carbide cylindrical rods were prepared by electron bombardment fusion and continuous casting in an apparatus making it possible to operate in a constant vacuum automatically. In order to make the most of the fusion technique used, it was necessary to resolve a certain number of problems involved in this production. It was found that the energy yield for the electron bombardment heating using accelerating voltages of about 10 kV was 100 per cent; about 40 per cent of the electrons are re-emitted by back-scattering. These electrons leave the surface with practically zero energy. The fusion technique leads to the elimination of the majority of the metallic impurities. In order to explain the variations in the non-metallic impurity contents the different reactions occurring in the molten uranium monocarbide have been determined. A micrographic study of the rods obtained has shown various types of crystallization depending on the rate of casting and, despite the uniaxial symmetry of the cooling, no texture has been observed, whatever the rate of fusion employed. The aspects of the fracture surfaces observed on certain rods can be explained by theory in the domain where the material is elastic. Furthermore it has been shown that a decrease in the brittleness occurs as a result of the formation of fine precipitates of the Wiedmanstatten structure type. (authors) [French] Au cours d'une fabrication pilote, environ 1 200 kg de barreaux cylindriques de carbure d'uranium ont ete prepares par fusion sous bombardement d'electrons et coulee continue dans un appareillage permettant d'operer d'une maniere automatique sous vide constant. Afin de tirer le meilleur parti possible de la technique de fusion utilisee, il importait de repondre a un certain nombre de questions soulevees par cette fabrication. Le rendement energetique du chauffage par bombardement d'electrons pour des tensions acceleratrices de l'ordre de 10 kV a ete

  1. Use of positive ion fast atom bombardment mass spectrometry for rapid identification of a bile alcohol glucuronide isolated from cerebrotendinous xanthomatosis patients

    International Nuclear Information System (INIS)

    Dayal, B.; Salen, G.; Tint, G.S.; Shefer, S.; Benz, S.W.

    1990-01-01

    The identification of a major biliary and plasma bile alcohol glucuronide, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol-3-0-beta-D-glucuronide, present in cerebrotendinous xanthomatosis (CTX) patients, was investigated by positive ion fast atom bombardment mass spectrometry (FAB-MS). The spectrum was characterized by abundant ions formed by attachment of a proton, [M + H]+, or of alkali ions, [M + Na]+ and [M + 39K]+, to the glucuronide salt. These ions allowed an unambiguous deduction of the molecular weight of the sample. It is suggested that FAB-MS could be used in the rapid diagnosis of CTX

  2. In situ ion etching in a scanning electron microscope

    International Nuclear Information System (INIS)

    Dhariwal, R.S.; Fitch, R.K.

    1977-01-01

    A facility for ion etching in a scanning electron microscope is described which incorporates a new type of electrostatic ion source and viewing of the specimen is possible within about 30 sec after terminating the ion bombardment. Artefacts produced during etching have been studied and cone formation has been followed during its growth. The instrument has provided useful structural information on metals, alloys, and sinters. However, although insulating materials, such as plastics, glass and resins, have been successfully etched, interpretation of the resultant micrographs is more difficult. Ion etching of soft biological tissues, such as the rat duodenum was found to be of considerable interest. The observed structural features arise from the selective intake of the heavy fixation elements by different parts of the tissue. Hard biological materials, such as dental tissues and restorative materials, have also been studied and the prismatic structure of the enamel and the form and distribution of the dentinal tubules have been revealed. (author)

  3. Secondary ions produced from condensed rare gas targets under highly charged MeV/amu heavy ion bombardment

    International Nuclear Information System (INIS)

    Tawara, H.; Tonuma, T.; Kumagai, H.; Matsuo, T.

    1994-01-01

    Secondary ions produced from condensed rare gas targets are observed under MeV/amu, highly charged, heavy ion impact. The intensities of the observed cluster ions decrease smoothly as the cluster sizes become large but show some discontinuities at particular sizes of cluster ions. This seems to be closely related to the stabilities of cluster ion structures. It is also noted that very few doubly charged or practically no triply/higher charged ions have been observed, in sharp contrast to that of some condensed molecular targets. (orig.)

  4. A comparison between the irradiation damage response of spinel and zirconia due to Xe ion bombardment

    International Nuclear Information System (INIS)

    Sickafus, K.E.; Wetteland, C.J.; Baker, N.P.; Yu Ning; Devanathan, R.; Nastasi, M.; Bordes, N.

    1998-01-01

    The mechanical properties of Xe-implanted spinel and cubic zirconia surfaces, as determined by nano-indentation measurements, are distinct and the differences can be related to their microstructures. Upon Xe 2+ ion irradiation to high dose at cryogenic temperature (120 K), the Young's modulus of irradiated spinel falls dramatically until the modulus is only about 3/4 the un-irradiated value. The maximum modulus occurs concurrent with the formation of a metastable crystalline phase of spinel. The subsequent elastic softening at higher Xe 2+ doses is an indication of the onset of amorphization of the spinel. Xe-implanted zirconia surfaces behave differently, in all cases showing almost no change in elastic modulus with increasing Xe 2+ ion dose. This is consistent with microstructural observations of Xe-implanted zirconia crystals which, unlike spinel, show no change in crystal structure with increasing ion dose. The hardness of both spinel and zirconia increases slightly for low Xe 2+ ion doses. At higher doses, zirconia shows little change in hardness, while the hardness of the implanted spinel falls by more than a factor of two. The initial increase in hardness of both spinel and zirconia is consistent with point defect accumulation and the precipitation of small interstitial clusters, while the drop in hardness of spinel at high Xe 2+ ion doses is due to the formation of an amorphous phase. (orig.)

  5. Effect of N4+ and C4+ ion beam bombardment on the optical and structural characteristics of ethylene-norbornene copolymer (TOPAS)

    International Nuclear Information System (INIS)

    Siljegovic, M.; Kacarevic-Popovic, Z.M.; Krkljes, A.N.; Stojanovic, Z.; Jovanovic, Z.M.

    2011-01-01

    Ion bombardment is a suitable tool to modify the optical properties of polymers. In the present study the effect of ion bombardment on the optical absorption of ethylene-norbornene copolymer (TOPAS) was studied using ultraviolet-visible (UV-Vis) and Raman spectroscopy. Polymer samples were bombarded with 60 keV C 4+ and N 4+ ion beams to various fluences ranging from 1.0 x 10 13 to 1.0 x 10 16 cm -2 . The indirect and direct band gaps have been determined. The values of direct band gaps have been found to be greater than the corresponding values of the indirect band gaps. Activation energy has been investigated as the function of ion fluences. The number of carbon atoms per conjugated length is determined according to modified Tauc's equation. The correlation between the optical band gap, activation energy for optical transition and the number of carbon atoms per conjugated length as well as chemical structure changes induced by ion beams irradiation have been discussed in the case of ethylene-norbornene copolymer.

  6. Monte Carlo simulation for neutron yield produced by bombarding thick targets with high energy heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Oh, Joo Hee; Yoon, Moo Hyun; Lee, Hee Seock [POSTECH, Pohang (Korea, Republic of)

    2013-04-15

    One of radiation shielding issues at heavy-ion accelerator facilities is to estimate neutron production by primary heavy ions. A few Monte Carlo transport codes such as FLUKA and PHITS can work with primary heavy ions. Recently IBS/RISP((Rare Isotope Science Project) started to design a high-energy, high-power rare isotope accelerator complex for nuclear physics, medical and material science and applications. There is a lack of experimental and simulated data about the interaction of major beam, {sup 238}U with materials. For the shielding design of the end of first accelerating section section, we calculate a differential neutron yield using the FLUKA code for the interaction of 18.5 MeV/u uranium ion beam with thin carbon stripper of 1.3 μm). The benchmarking studies were also done to prove the yield calculation for 400 MeV/n {sup 131}Xe and other heavy ions. In this study, the benchmarking for Xe-C, Xe-Cu, Xe-Al, Xe-Pb and U-C, other interactions were performed using the FLUKA code. All of results show that the FLUKA can evaluate the heavy ion induced reaction with good uncertainty. For the evaluation of neutron source term, the calculated neutron yields are shown in Fig. 2. The energy of Uranium ion beam is only 18.5 MeV/u, but the energy of produced secondary neutrons was extended over 100 MeV. So the neutron shielding and the damage by those neutrons is expected to be serious. Because of thin stripper, the neutron intensity at forward direction was high. But the the intensity of produced secondary photons was relatively low and mostly the angular property was isotropic. For the detail shielding design of stripper section of RISP rare istope accelerator, the benchmarking study and preliminary evaluation of neutron source term from uranium beam have been carried out using the FLUKA code. This study is also compared with the evaluation results using the PHITS code performed coincidently. Both studies shows that two monte carlo codes can give a good results for

  7. Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System

    Directory of Open Access Journals (Sweden)

    Philippe Boduch

    2011-01-01

    Full Text Available Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc. of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.

  8. Z1 dependence of ion-induced electron emission from aluminum

    International Nuclear Information System (INIS)

    Alonso, E.V.; Baragiola, R.A.; Ferron, J.; Jakas, M.M.; Oliva-Florio, A.

    1980-01-01

    We have measured the electron emission yields γ of clean aluminum under bombardment with H + , H 2 + , D + , D 2 + , He + , B + , C + , N + , N 2 + , O + , O 2 + , F + , Ne + , S + , Cl + , Ar + , Kr + , and Xe + in the energy range 1.2--50 keV. The clean surfaces were prepared by in situ evaporation of high-purity Al under ultra-high-vacuum conditions. It is found that kinetic electron emission yields γ/sub k/, obtained after subtracting from the measured γ a contribution due to potential emission, are roughly proportional to the electronic stopping powers, for projectiles lighter than Al. For heavier projectiles there is a sizable contribution to electron emission from collisions involving rapidly recoiling target atoms, which increases with the mass of the projectile, and which dominates the threshold and near-threshold behavior of kinetic emission. The results, together with recently reported data on Auger electron emission from ion-bombarded Al show that the mechanism proposed by Parilis and Kishinevskii of inner-shell excitation and subsequent Auger decay is negligible for light ions and probably small for heavy ions on Al and in our energy range. We thus conclude that kinetic electron emission under bombardment by low-energy ions results mainly from the escape of excited valence electrons

  9. Secondary ion emission from metal surfaces bombarded by 0.5-10 keV protons and hydrogens

    International Nuclear Information System (INIS)

    Kitamura, Akira; Yano, Syukuro

    1978-01-01

    Secondary ion emission coefficients by bombardment of 0.5 - 10 keV protons K 11 and atomic hydrogens K 01 on copper, stainless steel, molybdenum and evaporated gold surfaces have been measured in a moderate vacuum. Results are summarized as follows; 1) There is no significant difference between K 11 and K 01 . 2) Differences in K 11 and K 11 between different samples of the same material and between the sample before baking-out and the same sample after baking-out are of the order of several tens of percent. 3) The incident particle energy E sub(max) at which K 11 and K 01 have the maximum value lies in the keV region, and increases with the target mass. According to the fact that E sub(max) differs substantially from the energy at which the elastic stopping power has the maximum value, a characteristic length l is introduced and calculated to be of the order of hundreds of A; the factor exp (-x/l) represents the degree of contribution of collision at depth x to K 11 or K 01 . (author)

  10. Secondary ion emission from cleaned surfaces bombarded by 100 MeV accelerator beams at the GSI Darmstadt

    International Nuclear Information System (INIS)

    Wien, K.; Becker, O.; Guthier, W.; Knippelberg, W.; Koczon, P.

    1988-01-01

    The 1.4 MeV/n beam facility for the UNILAC/GSI has been used to study secondary ion emission from surfaces cleaned under UHV conditions by ion etching or cleaving of crystals. The desorption phenomena observed by means of TOF mass spectrometry can be classified as follows: (1) Clean metal surfaces emit metal ions being ejected by atomic collisions cascades. Electronic excitation of surface states seems to support ionization. (2) The desorption of contaminants adsorbed at the metal surface is strongly correlated with the electronic energy loss of the projectiles - even, if the content of impurities is very low. (3) Ion formation at the epitaxial surface of fluoride crystals as CaF 2 , MgF 2 and NaF is initiated by the electronic excitation of the crystal. At high beam energies the mass spectrum is dominated by a series of cluster ions. These cluster ions disappear below a certain energy deposit threshold, whereas small atomic ions are observed over the whole energy range

  11. The influence of ion energy, target temperature, dose rate and crystal order on the shape of bombardment induced pyramids on copper crystals

    International Nuclear Information System (INIS)

    Tanovic, L.; Whitton, J.L.; Kofod, S.

    1978-01-01

    Following recent studies of energetic ion bombardment of copper, which established the conditions necessary for the production of cones/pyramids, investigations have been extended to include the effects of change in ion energy, target temperature and dose rate. In addition, the authors have attempted a detailed analysis of the influence of sample crystal orientation on the final form of pyramids and have investigated the stability of the pyramids as a function of the total dose. These experiments, as in earlier work, have been done using very pure copper, mass-analyzed ion beams and free of any metal contamination from, for example, defining apertures. (Auth.)

  12. Electron capture by highly charged low-velocity ions

    International Nuclear Information System (INIS)

    Cocke, C.L.; Dubois, R.; Justiniano, E.; Gray, T.J.; Can, C.

    1982-01-01

    This paper describes the use of a fast heavy ion beam to produce, by bombardment of gaseous targets, highly-charged low-velocity recoil ions, and the use of these secondary ions in turn as projectiles in studies of electron capture and ionization in low-energy collision systems. The interest in collisions involving low-energy highly-charged projectiles comes both from the somewhat simplifying aspects of the physics which attend the long-range capture and from applications to fusion plasmas, astrophysics and more speculative technology such as the production of X-ray lasers. The ions of interest in such applications should have both electronic excitation and center-of-mass energies in the keV range and cannot be produced by simply stripping fast heavy ion beams. Several novel types of ion source have been developed to produce low-energy highly-charged ions, of which the secondary ion recoil source discussed in this paper is one. (Auth.)

  13. Data on ionization, excitation, dissociation and dissociative ionization of targets by helium ion bombardments, (1)

    International Nuclear Information System (INIS)

    Oda, Nobuo; Urakawa, Junji

    1984-03-01

    This report presents a compilation of the experimental data on cross sections for the ionization, excitation, dissociation and dissociative ionization processes of targets in helium ion impacts on atoms and molecules under a single collision condition. These measurements were carried out in the energy range from several keV to 3.5 MeV. A systematic survey has been made on the literatures from 1975 to the end of 1982. A list of references is also given, including relevant papers published before 1975. (author)

  14. Study of beryllium redeposition under bombardment by high intensity -low energy- hydrogen ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Gureev, V.M.; Guseva, M.I.; Danelyan, L.S. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)] [and others

    1998-01-01

    The results of studying the erosion of beryllium under an effect of intense ion fluxes with the energy of 250 eV, at the fluences {approx}10{sup 2}1 cm{sup -2}, at the MAGRAS-stand are given. The operating conditions under which a practically-complete redeposition of the sputtered beryllium upon the target surface were experimentally-realized. A change in the microstructure of a beryllium target under sputtering and redeposition is analyzed. Some technological applications are considered. (author)

  15. Comparison of electron ionization and fast atom bombardment-mass spectrometry for the determination of nickel, vanadyl and free-base porphyrins

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A.J.; Van Berkel, G.J.; Doolittle, F.G.; Filby, R.H. (Washington State Univ., Pullman (USA))

    1989-01-01

    Fast Atom Bombardment-Mass Spectrometry (FAB-MS) and Electron Ionization-Mass Spectrometry (EI-MS) at 12 and 70 eV, were used to obtain mass spectra of mesoporphyrin IX dimethylester (DME), tetraphenylporphyrin (TPP), octaethylporphyrin (OEP), and the metal-loporphyrins, Ni(DME), Ni(TPP), Ni(OEP), VO(TPP), VO(OEP), as well as a VO(II) porphyrin concentrate obtained from the New Albany oil shale bitumen (Mississippian-Devonian). A mixture of dithiothreitol/dithioerythritol (Magic Bullet) was used as the FAB matrix. Greater fragmentation of free-base and metalloporphyrins was observed in FAB mass spectra compared to the EI mass spectra. Adduct ions formed by addition of sulfur and a matrix molecule to the porphyrins were observed. In FAB spectra of the VO(II) complexes, loss of oxygen was noted. The FAB mass spectra of mixtures of VO(II) geoporphyrins are much more complex than corresponding EI mass spectra because of the greater fragmentation and the multiplicity of ions (M{sup +}, M + H, M + 2H, etc.) observed in the FAB mode. Using the matrices investigated, FAB is less suitable for EI for the mass spectrometric analysis of the geoporphyrins.

  16. Silicide formation by Ar/sup +/ ion bombardment of Pd/Si

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R Y; Whang, C N; Kim, H K; Smith, R J

    1988-08-01

    Palladium films, 45 nm thick, evaporated on to Si(111) were irradiated to various doses with 78 keV Ar/sup +/ ions to promote silicide formation. Rutherford backscattering spectroscopy (RBS) shows that intermixing has occurred across the Pd/Si interface at room temperature. The mixing behaviour is increased with dose which coincides well with the theoretical model of cascade mixing. The absence of deep RBS tails for palladium and the small area of this for silicon spectra indicate that short-range mixing occurs. From the calculated damage profiles computed with TRIM code, the dominant diffusion species is found to be silicon atoms in the Pd/Si system. It is also found that the initial compound formed by Ar/sup +/ irradiation is Pd/sub 2/Si which increases with dose. At a dose of 1 x 10/sup 16/ Ar/sup +/ cm/sup -2/, a 48 nm thickness of Pd/sub 2/Si was formed by ion-beam mixing at room temperature.

  17. Reducing the impurity incorporation from residual gas by ion bombardment during high vacuum magnetron sputtering

    International Nuclear Information System (INIS)

    Rosen, Johanna; Widenkvist, Erika; Larsson, Karin; Kreissig, Ulrich; Mraz, Stanislav; Martinez, Carlos; Music, Denis; Schneider, J. M.

    2006-01-01

    The influence of ion energy on the hydrogen incorporation has been investigated for alumina thin films, deposited by reactive magnetron sputtering in an Ar/O 2 /H 2 O environment. Ar + with an average kinetic energy of ∼5 eV was determined to be the dominating species in the plasma. The films were analyzed with x-ray diffraction, x-ray photoelectron spectroscopy, and elastic recoil detection analysis, demonstrating evidence for amorphous films with stoichiometric O/Al ratio. As the substrate bias potential was increased from -15 V (floating potential) to -100 V, the hydrogen content decreased by ∼70%, from 9.1 to 2.8 at. %. Based on ab initio calculations, these results may be understood by thermodynamic principles, where a supply of energy enables surface diffusion, H 2 formation, and desorption [Rosen et al., J. Phys.: Condens. Matter 17, L137 (2005)]. These findings are of importance for the understanding of the correlation between ion energy and film composition and also show a pathway to reduce impurity incorporation during film growth in a high vacuum ambient

  18. Nonlinear Amplitude Evolution During Spontaneous Patterning of Ion-Bombarded Si(001)

    International Nuclear Information System (INIS)

    Chason, Eric; Erlebacher, Jonah; Aziz, Michael J.; Floro, Jerold A.; Sinclair, Michael B.

    1999-01-01

    The time evolution of the amplitude of periodic nanoscale ripple patterns formed on Ar+ sputtered Si(OOl ) surfaces was examined using a recently developed in situ spectroscopic technique. At sufficiently long times, we find that the amplitude does not continue to grow exponentially as predicted by the standard Bradley-Harper sputter rippling model. In accounting for this discrepancy, we rule out effects related to the concentration of mobile species, high surface curvature, surface energy anisotropy, and ion-surface interactions. We observe that for all wavelengths the amplitude ceases to grow when the width of the topmost terrace of the ripples is reduced to approximately 25 nm. This observation suggests that a short circuit relaxation mechanism limits amplitude . growth. A strategy for influencing the ultimate ripple amplitude is discussed

  19. Controllable fabrication of amorphous Si layer by energetic cluster ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vorlíček, Vladimír; Dejneka, Alexandr; Chvostová, Dagmar; Jäger, Aleš; Vacík, Jiří; Jastrabík, Lubomír; Naramoto, H.; Narumi, K.

    2013-01-01

    Roč. 98, SI (2013), s. 49-55 ISSN 0042-207X R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : energetic cluster s * silicon * surface modification * amorphization * nanostructure * Raman scattering * ion channeling Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 1.426, year: 2013 http://ac.els-cdn.com/S0042207X13001759/1-s2.0-S0042207X13001759-main.pdf?_tid=04e9c946-21dd-11e3-b076-00000aacb361&acdnat=1379672070_859355b2850a09ac74bc8ff413e35dda

  20. Electron-positron pair creation in heavy ion collisions

    International Nuclear Information System (INIS)

    Kienle, P.

    1987-08-01

    We review here the status of experiments to study the electron positron pair creation in heavy ion atom collisions at bombarding energies close to the Coulomb barrier. The disentanglement and characterisation of various sources of positrons observed in such collisions are described with a focus on the monoenergetic electron positron pairs observed. They seem to originate from the two-body decay of a family of neutral particles with masses of about 3 m e and life times in the range of 6x10 -14 s -10 s, produced by high Coulomb fields. First attempts were made to create these particles by resonant Bhabha scattering. First we present some experimental methods for high efficiency positron spectroscopy in heavy ion collisions. Then we describe the discovery of positron creation induced by strong time changing Coulomb fields. (orig./HSI)

  1. Application of alpha spectrometry to the discovery of new elements by heavy-ion-beam bombardment

    International Nuclear Information System (INIS)

    Nitschke, J.M.

    1983-05-01

    Starting with polonium in 1898, α-spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, α-spectra have proved simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the natural α-decay series led to the very powerful method of genetically linking the decay of new elements to the well-established α-emission of daughter and granddaughter nuclei. This technique has been used for all recent discoveries of new elements including Z = 109. Up to mendelevium (Z = 101), thin samples suitable for α-spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in He gas. Subsequent electrical deposition or a He-jet technique yielded samples that were not only thin enough for α-spectroscopy, but also for α- and #betta#-recoil experiments. Many variations of these methods have been developed and are discussed. For the synthesis of element 106 an aerosol-based recoil transport technique was devised. In the most recent experiments, α-spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10 - 6 s; while it was 10 - 1 to 10 0 s for He-jets and 10 1 to 10 3 s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyze them with these latest techniques. Again, α-spectrometry will play a major role since the expected signature for the decay of a SHE is a sequence of α-decays followed by spontaneous fission

  2. Formation of Amino Acid Precursors by Bombardment of Interstellar Ice Analogs with High Energy Heavy Ions

    Science.gov (United States)

    Kobayashi, Kensei; Mita, Hajime; Yoshida, Satoshi; Shibata, Hiromi; Enomoto, Shingo; Matsuda, Tomoyuki; Fukuda, Hitoshi; Kondo, Kotaro; Oguri, Yoshiyuki; Kebukawa, Yoko

    2016-07-01

    A wide variety of organic compounds have been detected in extraterrestrial bodies. It has been recognized that carbonaceous chondrites contain pristine amino acids [1]. There are several scenarios of the formation of such extraterrestrial amino acids or their precursors. Greenberg proposed a scenario that complex organic compounds were formed in interstellar ices in dense clouds, which were brought into solar system small bodies when the solar system was formed [2]. The ice mantles of interstellar dust particles (ISDs) in dense clouds are composed of H2O, CO, CH3OH, CH4, CO2, NH3, etc. In order to verify the scenario, a number of laboratory experiments have been conducted where interstellar ice analogs were irradiated with high-energy particles [3,4] or UV [5,6], and formation of complex organic compounds including amino acid precursors were detected in the products. Though ion-molecular reactions in gaseous phase and surface reactions on the ice mantles have been studied intensively, much less works on cosmic rays-induced reaction have been reported. In order to study possible formation of complex molecules in interstellar ices, frozen mixtures of water, methanol and ammonia with various mixing ratios were irradiated with high-energy heavy ions such as carbon ions (290 MeV/u) and neon ions (400 MeV/u) from HIMAC, NIRS, Japan. For comparison, gaseous mixtures of water, ammonia, carbon monoxide, carbon dioxide, and/or methane were irradiated with protons (2.5 MeV) from a Tandem accelerator, Tokyo Tech, Japan. Amino acids in the products were determined by cation exchange HPLC after acid hydrolysis. Products, both before and after acid hydrolysis, were also characterized by FT-IR and other techniques. Amino acids were detected in the hydrolyzed products after mixture of CH3OH, NH3 and H2O with various mixing ratios were irradiated with heavy ions, including when their mixing ratio was set close to the reported value of the interstellar ices (10:1:37). In the HIMAC

  3. CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

    Science.gov (United States)

    Rupprechter, G.; Kaichev, V. V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V. I.

    2004-07-01

    The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H 2 mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH xO species as precursors for CO bond cleavage and that the formation of CH xO is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

  4. CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

    Energy Technology Data Exchange (ETDEWEB)

    Rupprechter, G.; Kaichev, V.V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V.I

    2004-07-31

    The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H{sub 2} mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH{sub x}O species as precursors for C---O bond cleavage and that the formation of CH{sub x}O is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

  5. Using MDECR-PECVD to study the impact of ion bombardment energy on microstructural properties of μc-Si:H thin film grown from an SiF{sub 4}/H{sub 2} chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Junkang; Florea, Ileana; Bulkin, Pavel V.; Maurice, Jean-Luc; Johnson, Erik V. [LPICM, CNRS, Ecole Polytechnique, Universite Paris Saclay, 91128 Palaiseau (France)

    2016-12-15

    The matrix-distributed electron cyclotron resonance plasma-enhanced chemical vapor deposition (MDECR-PECVD) technique has been shown to achieve high deposition rates for hydrogenated microcrystalline silicon (μc-Si:H) thin film. Due to the fact that plasma is sustained by a microwave discharge, by biasing the substrate holder with additional power supply, one can achieve independent control over the plasma density and the maximum ion bombardment energy (IBE). In this work, we present studies of the impact of IBE on the microstructural properties of the μc-Si:H film deposited by MDECR-PECVD. Insufficient ion bombardment is found to be responsible for the substantial presence of nano-porous regions within the material, resulting in significant post-deposition oxidation. Good agreement between transmission electron microscopy (TEM) Fresnel contrast analysis and the results of infrared absorption and hydrogen effusion measurements for the deposited films suggest that moderate IBE is of vital importance to achieve high quality μc-Si:H. In doing so, denser films with significantly decreased nano-porous regions and better stability are obtained, which is of great interest to optimize the process parameters for solar cell applications. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Influence of ion bombardment on structural and electrical properties of SiO2 thin films deposited from O2/HMDSO inductively coupled plasmas under continuous wave and pulsed modes

    International Nuclear Information System (INIS)

    Bousquet, A.; Goullet, A.; Leteinturier, C.; Granier, A.; Coulon, N.

    2008-01-01

    Low pressure Plasma Enhanced Chemical Vapour Deposition is commonly used to deposit insulators on temperature sensitive substrates. In these processes, the ion bombardment experienced by films during its growth is known to have benefits but also some disadvantages on material properties. In the present paper, we investigate the influence of this bombardment on the structure and the electrical properties of SiO 2 -like film deposited from oxygen/hexa-methyl-di-siloxane radiofrequency plasma in continuous and pulsed modes. First, we studied the ion kinetics thanks to time-resolved measurements by Langmuir probe. After, we showed the ion bombardment in such plasma controls the OH bond content in deposited films. Finally, we highlight the impressive reduction of fixed charge and interface state densities in films obtained in pulsed mode due to a lower ion bombardment. (authors)

  7. Experimental and theoretical studies of bombardment induced surface morphology changes

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.; Williams, J.S.

    1980-01-01

    In this review results of experimental and theoretical studies of solid surface morphology changes due to ion bombardment are discussed. An attempt is undertaken to classify the observed specific features of a structure, generated by ion bombardment [ru

  8. Vacancy production in molybdenum by low energy light ion bombardment: computer simulation

    International Nuclear Information System (INIS)

    Hou, M.; Veen, A. van; Caspers, L.M.; Ypma, M.R.

    1983-01-01

    A comparison is made of the room temperature vacancy production measured with THDS (thermal helium desorption spectrometry) and the Frenkel pair production calculated in the binary collision approximation with MARLOWE for 0.5 to 3 keV He + ions and 1.5 keV protons injected into a Mo(110) crystal. Using the distributions of Frenkel pair separation distances calculated with MARLOWE for various values of the displacement threshold Esub(d), the experimental data are matched by selecting a cut-off radius Rsub(c) so that for separations larger than Rsub(c) the Frenkel pairs survive recombination. It became apparent that all experimental data could be reasonably described by a pair of parameters Esub(d) = 33 eV and Rsub(c) = 3.7 a 0 (a 0 is the lattice cell edge unit). The value of Esub(d) we found is close to the experimentally determined threshold energy for permanent displacements in Mo. A detailed analysis of the recombination process using the MARLOWE results shows that the found cut-off radius corresponds with an effective recombination radius Rsub(o) = 2.8 a 0 . In the literature lower (theoretical) values of Rsub(o) = 1.4 - 2.1 a 0 are quoted for correlated recombination of single Frenkel pairs in molybdenum. (orig.)

  9. Electron cloud and ion effects

    CERN Document Server

    Arduini, Gianluigi

    2002-01-01

    The significant progress in the understanding and control of machine impedances has allowed obtaining beams with increasing brilliance. Dense positively charged beams generate electron clouds via gas ionization, photoemission and multipacting. The electron cloud in turn interacts with the beam and the surrounding environment originating fast coupled and single bunch instabilities, emittance blow-up, additional loads to vacuum and cryogenic systems, perturbation to beam diagnostics and feedbacks and it constitutes a serious limitation to machine performance. In a similar way high brilliance electron beams are mainly affected by positively charged ions produced by residual gas ionization. Recent observations of electron cloud build-up and its effects in present accelerators are reviewed and compared with theory and with the results of state-of-the-art computer simulations. Two-stream instabilities induced by the interaction between electron beams and ions are discussed. The implications for future accelerators ...

  10. ANALYTICAL MODELING OF ELECTRON BACK-BOMBARDMENT INDUCED CURRENT INCREASE IN UN-GATED THERMIONIC CATHODE RF GUNS

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, J. P. [Fermilab; Sun, Y. [Argonne; Harris, J. R. [AFRL, NM; Lewellen, J. W. [Los Alamos Natl. Lab.

    2016-09-28

    In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, fieldenhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.

  11. Dependence of secondary electron emission on the incident angle and the energy of primary electrons bombarding bowl-structured beryllium surfaces

    International Nuclear Information System (INIS)

    Kawata, Jun; Ohya, Kaoru.

    1994-01-01

    A Monte Carlo simulation of the secondary electron emission from beryllium is combined with a model of bowl structure for surface roughness, for analyzing the difference between the electron emissions for normal and oblique incidences. At normal incidence, with increasing the roughness parameter H/W, the primary energy E pm at which the maximum electron yield occurs becomes higher, and at more than the E pm , the decrease in the yield is slower; where H and W are the depth and width of the bowl structure, respectively. The dispersion of incident angle to the microscopic surface causes a small increase in the yield at oblique incidence, whereas the blocking of primary electrons from bombarding the bottom of the structure causes an opposite trend. The strong anisotropy in the polar angular distribution with respect to the azimuthal angle is calculated at oblique incidence. (author)

  12. Ion-Ion Plasmas Produced by Electron Beams

    Science.gov (United States)

    Fernsler, R. F.; Leonhardt, D.; Walton, S. G.; Meger, R. A.

    2001-10-01

    The ability of plasmas to etch deep, small-scale features in materials is limited by localized charging of the features. The features charge because of the difference in electron and ion anisotropy, and thus one solution now being explored is to use ion-ion plasmas in place of electron-ion plasmas. Ion-ion plasmas are effectively electron-free and consist mainly of positive and negative ions. Since the two ion species behave similarly, localized charging is largely eliminated. However, the only way to produce ion-ion plasmas at low gas pressure is to convert electrons into negative ions through two-body attachment to neutrals. While the electron attachment rate is large at low electron temperatures (Te < 1 eV) in many of the halogen gases used for processing, these temperatures occur in most reactors only during the afterglow when the heating fields are turned off and the plasma is decaying. By contrast, Te is low nearly all the time in plasmas produced by electron beams, and therefore electron beams can potentially produce ion-ion plasmas continuously. The theory of ion-ion plasmas formed by pulsed electron beams is examined in this talk and compared with experimental results presented elsewhere [1]. Some general limitations of ion-ion plasmas, including relatively low flux levels, are discussed as well. [1] See the presentation by D. Leonhardt et al. at this conference.

  13. Experimental study of secondary ion emission from bombarded surfaces by heavy ions at nucleon energy between 0.1 and 5 MeV/u

    International Nuclear Information System (INIS)

    Lorthiois, I.

    1983-03-01

    A time of flight mass spectrometer associated with 252 Cf has been built in the laboratory and used to identify organic and biological molecules. A few number of examples is shown. The complex interaction processes between primary ions and several kinds of materials can be more easily studied by using heavy ions from an accelerator. The mass of the primary ions, its velocity and its state charge are known parameters wich can be varied in these experiments. The desorption yields have been measured simultaneously with other parameters (velocity of the primary ions, number of emitted electrons). The velocity dependance of the yield shows the existence of a maximum around 1 cm/ns and no direct correlations have been found between the yield curves and the electronic stopping power (dE/dx). Experimental results are presented for several types of primary ions (Cu, Kr, Ag) and of material deposits [fr

  14. Damage of niobium surfaces caused by bombardment with 4He+ ions of different energies typical for T-20

    International Nuclear Information System (INIS)

    Guseva, M.I.; Gusev, V.; Martynenko, Yu.V.; Das, S.K.; Kaminsky, N.

    1979-01-01

    The surface damage of cold worked and annealed polycrystalline Nb irradiated at room temperature with He + ions sequentially at different energies over the range from 0.5 keV to 1.8 MeV has been investigated. The individual energy and the dose of the He + ion was chosen to match the theoretically calculated He + ion spectrum expected in the Tokamak T-20. In one set of irradiations, targets were irradiated at Kurchatov Institute starting with 0.5 keV 4 He + ions and extending up to 90 keV in eleven steps. Subsequently, the same area was irradiated at ANL starting at 150 keV and increased in eight steps up to 1.8 MeV. The irradiations were carried out for a total dose of 5.0 C/cm 2 . In another set of irradiations the sequence was reversed. Scanning electron microscopy results show formation of blisters and exfoliation. For the same dose the broad energy implant (due to sequential irradiation) appears to decrease the blister diameter and density as compared to irradiation with monoenergetic He + ions at a given energy (in the energy range considered). Some estimates of surface erosion yields due to blistering are given

  15. A possible mechanism for electron-bombardment-induced loop punching in helium-implanted materials

    International Nuclear Information System (INIS)

    Donnelly, S.E.

    1983-01-01

    The recently proposed mechanism for the punching of dislocation loops by overpressurized helium bubbles in molybdenum is studied quantitatively. According to this mechanism, under the electron beam of the transmission microscope, He atoms are excited or ionized and the resulting excited species (excited He atoms and free electrons) are responsible for the pressure rise in the gas beyond the threshold for loop punching. In the model, the pressure increase is attributed to a reduction of the effective volume accessible to the gas due to the formation of a cavity around each excited species. The radius of this cavity is evaluated and, also, the excited fraction required to reach the threshold is discussed in terms of excitation life times. (author)

  16. Distributions of neutron yields and doses around a water phantom bombarded with 290-MeV/nucleon and 430-MeV/nucleon carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, D., E-mail: satoh.daiki@jaea.go.jp [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kajimoto, T. [Hiroshima University, Kagamiyama, Higashi-Hiroshima-shi, Hiroshima 739-8527 (Japan); Shigyo, N.; Itashiki, Y.; Imabayashi, Y. [Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Koba, Y.; Matsufuji, N. [National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Sanami, T. [High Energy Accelerator Research Organization, Oho-cho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Nakao, N. [Shimizu Corporation, Etchujima, Koto-ku, Tokyo 135-8530 (Japan); Uozumi, Y. [Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2016-11-15

    Double-differential neutron yields from a water phantom bombarded with 290-MeV/nucleon and 430-MeV/nucleon carbon ions were measured at emission angles of 15°, 30°, 45°, 60°, 75°, and 90°, and angular distributions of neutron yields and doses around the phantom were obtained. The experimental data were compared with results of the Monte-Carlo simulation code PHITS. The PHITS results showed good agreement with the measured data. On the basis of the PHITS simulation, we estimated the angular distributions of neutron yields and doses from 0° to 180° including thermal neutrons.

  17. Surface temperature measurements for ion-bombarded Si and GaAs at 1.0 to 2.0 MeV

    International Nuclear Information System (INIS)

    Lowe, L.F.; Kennedy, J.K.; Davies, D.E.; Deane, M.L.; Eyges, L.J.

    1975-01-01

    Surface temperatures of ion-bombarded silicon and gallium arsenide have been measured using an infrared detector. Ion beams of N + , N + 2 , O + , O + 2 , C + , CO + , and H + were used at energies from 1--2.0 MeV and at current densities up to 12 μAcenter-dotcm/sup -2/. No temperature dependence was found on ion species, energy, or current. The change in temperature depended only on beam power, target material, and sample mounting technique. With proper mounting temperature increases of 20 degreeC for silicon and 65 degreeC for gallium arsenide were observed for a beam power density of 1.0 Wcenter-dotcm/sup -2/

  18. Spectroscopy of heavy few-electron ions

    International Nuclear Information System (INIS)

    Mokler, P.H.

    1986-07-01

    In this paper we ask first, why is it interesting to investigate heavy-few electron ions. Then the various accelerator-based methods to produce heavy few-electron ions are discussed. In the main part an overview on available heavy few-electron ion data and current experiments is given. The summary will end up with future aspects in this field. (orig.)

  19. Defect formation and desorption of metal atoms from alkali halide crystals under low energy electron bombardment studied by optical absorption and mass spectroscopy

    International Nuclear Information System (INIS)

    Seifert, N.R.

    1993-04-01

    This work presents an extensive investigation of electronically induced desorption of ground-state alkali atoms from alkali halides and for the first time correlates directly the desorption with the stability and spatial distribution of the defects formed during bombardment. The electron impact results in the formation of stable F-centers and F-center clusters in the bulk of the crystals. In striking contrast a significant metallization of the surface is observed. Even at temperatures as low as 90 deg C the metallization is achieved within the time resolution of our detection system, which can only be explained by the rapid diffusion of hot holes. Superimposed to the fast and short diffusion of hot holes is the slow F-center diffusion. Measuring the distribution of defects with low energy ion sputtering techniques indicates that at least in the case of LiF the observed diffusion constant of F-centers agrees with values derived by using methods different from that applied here. At low temperatures the formation of F-center clusters and metal on the surface dominates. Colloid formation clearly requires higher temperatures (typically around 200 deg C). This is a strong evidence that efficient F-center diffusion is necessary for the formation of metallic particles (colloids) in the bulk of the crystals. Desorption of alkali atoms from alkali halides at temperatures around room temperature is due to weakly bound alkali atoms. For elevated temperatures the stability of the metallic clusters in the bulk of the crystals (i.e. colloids) are the rate limiting process. (author)

  20. Cascade production of Ar(3p54p) following electron bombardment

    International Nuclear Information System (INIS)

    Keto, J.W.; Kuo, C.

    1981-01-01

    We observe the time dependence of the fluorescence of Ar(3p 5 4p) following electron excitation of argon at pressures from 2--3000 Torr. The population of these levels at the lowest pressures observed is dominated by radiative cascade from Ar(3p 5 3d) and Ar(3p 5 5s). For argon states 4p'[1/2] 0 , 4p'[3/2] 2 , and 4p[1/2] 0 we find the cascade transitions can be identified and we assign radiative lifetimes of 61 +- 10, 69 +- 12, and 61 +- 6 nsec to 3d'[3/2] 1 , 3d'[5/2] 3 , and 3d[3/2] 1 , respectively. For cascade lifetimes to other levels, unique assignments cannot be made until values for forbidden electron impact cross sections to 3p 5 3d and 3p 5 5s can be obtained. The collisional quenching rates for the cascading levels are measured and found to explain the pressure dependence of the decay of Ar(3p 5 4p) over the full range of pressure except for Ar(3p 5 4p'[1/2] 1 ) which has a unique and interesting behavior at high pressures

  1. Modification of Color Centers by Electron Bombardment: Final Report CRADA No. TC-0460-93-A

    Energy Technology Data Exchange (ETDEWEB)

    Van Bibber, Karl [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Alger, Don M. [Quali-Tech, Inc., Columbia, MO (United States)

    2000-11-30

    The purpose of the project was to: Identify those electron beam irradiation parameters most relevant to process quality and efficiency, to producing and modifying color centers in topaz. Develop and test improved radiation processing techniques, and evaluate their potential applicability to other types of semi-precious gems. Develop an optimized data base for the process and procedures for identifying and characterizing material from new and diverse sources. Transfer new processing technology to the private sector, and, until they are implemented industrially, to perform radiation dosing to partially satisfy existing excess demand. We planned to define the interaction between sample purity level, the physics of irradiation to achieve color cent-er modification on a reproducible basis and demonstration of the resulting process on a commercially viable basis. The primary deliverable was the increased knowledge base in terms of expanded understanding of the systematics of color center modification in materials, and an extensive database of electron beam parameters which would optimize the efficiency and quality of radiation processing of topaz from diverse sources. The radiation processing of these stones constitutes a deliverable to Quali-Tech by LLNL.

  2. Intense electron and ion beams

    CERN Document Server

    Molokovsky, Sergey Ivanovich

    2005-01-01

    Intense Ion and Electron Beams treats intense charged-particle beams used in vacuum tubes, particle beam technology and experimental installations such as free electron lasers and accelerators. It addresses, among other things, the physics and basic theory of intense charged-particle beams; computation and design of charged-particle guns and focusing systems; multiple-beam charged-particle systems; and experimental methods for investigating intense particle beams. The coverage is carefully balanced between the physics of intense charged-particle beams and the design of optical systems for their formation and focusing. It can be recommended to all scientists studying or applying vacuum electronics and charged-particle beam technology, including students, engineers and researchers.

  3. Nanoconstructive bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, J [VSW Ion Beam Systems, Warrington (UK)

    1990-06-01

    Ion beams with energies as low as a few eV can be used, in the very clean environment of an ultra-high vacuum system, to achieve the fine control for atomic-scale experiments. They are becoming widely used in nanotechnology. Recent advances in beam quality, overcoming the mutual repulsion of the ions, have meant that mass-analysed low energy ion beams have been developed around the world for a variety of applications in material science, and physics. The structure of such devices is outlined and possible future applications noted. (U.K.).

  4. Electron and ion beam degradation effects in AES analysis of silicon nitride thin films

    International Nuclear Information System (INIS)

    Fransen, F.; Vanden Berghe, R.; Vlaeminck, R.; Hinoul, M.; Remmerie, J.; Maes, H.E.

    1985-01-01

    Silicon nitride films are currently investigated by AES combined with ion profiling techniques for their stoichiometry and oxygen content. During this analysis, ion beam and primary electron effects were observed. The effect of argon ion bombardment is the preferential sputtering of nitrogen, forming 'covalent' silicon at the surface layer (AES peak at 91 eV). The electron beam irradiation results in a decrease of the covalent silicon peak, either by an electron beam annealing effect in the bulk of the silicon nitride film, or by an ionization enhanced surface diffusion process of the silicon (electromigration). By the electron beam annealing, nitrogen species are liberated in the bulk of the silicon nitride film and migrate towards the surface where they react with the covalent silicon. The ionization enhanced diffusion originates from local charging of the surface, induced by the electron beam. (author)

  5. Formation mechanism and yield of molecules ejected from ZnS, CdS, and FeS2 during ion bombardment

    International Nuclear Information System (INIS)

    Nikzad, S.; Calaway, W.F.; Pellin, M.J.; Young, C.E.; Gruen, D.M.; Tombrello, T.A.

    1994-01-01

    Neutral species ejected from single crystals of ZnS, CdS, and FeS 2 during ion bombardment by 3 keV Ar + were detected by laser post-ionization followed by time-of-flight mass spectrometry. While metal atoms (Fe, Zn, Cd) and S 2 were the dominant species observed, substantial amounts of S, FeS, Zn 2 , ZnS, Cd 2 , and CdS were also detected. The experimental results demonstrate that molecules represent a larger fraction of the sputtered yield than was previously believed from secondary ion mass spectrometry experiments. In addition, the data suggest that the molecules are not necessarily formed from adjacent atoms in the solid and that a modified form of the recombination model could provide a mechanism for their formation

  6. Secondary emission ion analyzer provided with an electron gun for insulating material analysis

    International Nuclear Information System (INIS)

    Blanchard, Bruno; Carrier, Patrick; Marguerite, J.-L.; Rocco, J.-C.

    1976-01-01

    This invention relates to a secondary emission ion analyser, fitted with an electron gun. It is used in the mass spectrometry analysis of electrically insulating bodies. It has already been suggested to bombard the target with an electron beam in conjunction with the beam of primary particles, in order to reduce the space charge near the target. The object of this invention is the application of this known process to appliances of the ion analyser type with a high electric field near the target. Its main characteristic is the use of an electron gun emitting an electron beam through the extraction lens placed opposite the target. The extraction electric field influences the path of the electrons but the electric and mechanical specifications of the electron gun in the invention are such that the target is correctly sprayed by the electron beam [fr

  7. Producing the radioelectric effect in solid dielectrics by bombardment with accelerated electrons. Obrazovaniye radioelektretnogo effekta v tverdykh dielektrikakh v rezul'tate oblucheniya ikh uskorennymi elektronami

    Energy Technology Data Exchange (ETDEWEB)

    Zavadovskaya, E K; Annenkov, Yu M; Boev, S G; Sigaev, G I

    1976-01-01

    A theoretical and experimental study was made concerning the kinetics of formation of electric moments in solid dielectrics bombarded with fast electrons in the atmosphere. The energy of bombarding electrons in the experiment ranged from 0.6 to 2.0 MeV, at an incident flux density ranging 1.10/sup -9/ to 5.10/sup -7/ A/cm/sup 2/. The specimens were actually grounded during bonbardment, owing to the high electrical conductivity of the ionized ambient gas, and the electric moments were equal to zero. The formation of electric moments occurred after cessation of the bombardment, because the density of the accumulated space charge had become redistributed. An examination was made of the redistribution of space-charge density due to the electrical conductivity of the dielectric, due to intrinsic charge carriers, and due to the release of charges stored in traps. Analytical relations derived for the kinetics of the electric moments give a qualitative description of the experimental results. 5 references.

  8. Study of the machining of uranium carbide rods obtained by continuous casting under electronic bombardment; Etude de l'usinage de barreaux de carbure d'uranium obtenus par coulee continue sous bombardement electronique

    Energy Technology Data Exchange (ETDEWEB)

    Rousset, P; Accary, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The authors consider the various methods of machining uranium mono-carbide and compare them critically in the case of their application to uranium carbide obtained by fusion under an electronic bombardment and continuous casting. This study leads them to propose two mechanical machining methods: cylindrical rectification and center-less rectification, preceded by a preliminary roughing out of a cylinder, the latter appearing more suitable. A study of the machining yields as a function of the diameter of the rough bars and of the diameter of the finished rods has shown that an optimum value of the rough bar diameter exists for each value of the finished rod diameter. It is found that the yield increases as the diameter itself increases, this yield rising from 45 per cent to around 70 per cent as the diameter of the rough bars increases from 25-26 mm to 37-38 mm. (authors) [French] Les auteurs envisagent les differentes methodes d'usinage du monocarbure d'uranium et se livrent a une etude critique de celles-ci, dans le cas de leur application a l'usinage de barreaux de carbure d'uranium obtenus par fusion sous bombardement electronique et coulee continue. Cette etude les conduit a proposer deux methodes d'usinage mecanique: la rectification cylindrique et la rectification 'centerless', precedee d'un ebauchage par carottage, la seconde paraissant la plus appropriee. L'etude des rendements d'usinage en fonction du diametre des barreaux bruts et du diametre des barreaux finis, a mis en evidence une valeur optimale du diametre des barreaux bruts pour chaque valeur du diametre des barreaux usines. Elle a montre que le rendement croit lorsque le diametre croit lui-meme, ce rendement passant d'environ 45 pour cent a environ 70 pour cent, lorsque le diametre des barreaux bruts passe de 25-26 mm a 37-38 mm.

  9. The effects of thermal annealing on iron bombarded InP/InGaAs multilayer structures

    International Nuclear Information System (INIS)

    Subramaniam, S.C.; Rezazadeh, A.A.

    2006-01-01

    The effects of Fe-ion bombardment at 77 K (cold) and room temperature (RT) into single layer InGaAs, InP and multilayer InP/InGaAs HBT structures have been investigated. Annealing characteristics and RF dissipation loss measurements of Fe-ion bombarded samples at 77 K indicated good electrical isolation in n-, p-type InGaAs materials and InP/InGaAs HBT structures. Thermally stable (up to 250 deg. C) high sheet resistance (R sh ) of ∼5 x 10 6 Ω/sq has been achieved on these samples while higher R sh of ∼10 7 Ω/sq was obtained for the n-InP materials bombarded with similar conditions. Dissipation losses of 1.7 dB/cm at 10 GHz and 2.8 dB/cm at 40 GHz have been measured for the cold Fe-ion bombarded InP-based HBT structures. This result is similar to those obtained for an un-bombarded S.I. InP substrate, indicating good electrical isolation. We have also determined electron trapping levels by thermal annealing for the cold and RT Fe-ion bombarded samples. It is shown that the high resistivity achieved in the cold implanted InGaAs layer is most likely due to the creation of mid-bandgap defect levels (E C - 0.33) eV, which are created only in the cold Fe-ion bombardment. The DC isolation and RF dissipation loss analysis have been used to identify a suitable bombardment scheme for the fabrication of planar InP/InGaAs HBTs

  10. Heavy-ion induced desorption yields of amorphous carbon films bombarded with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Küchler, D; Scrivens, R; Costa Pinto, P; Yin Vallgren, C; Bender, M

    2011-01-01

    During the past decade, intense experimental studies on the heavy-ion induced molecular desorption were performed in several particle accelerator laboratories worldwide in order to understand and overcome large dynamic pressure rises caused by lost beam ions. Different target materials and various coatings were studied for desorption and mitigation techniques were applied to heavy-ion accelerators. For the upgrade of the CERN injector complex, a coating of the Super Proton Synchrotron (SPS) vacuum system with a thin film of amorphous carbon is under study to mitigate the electron cloud effect observed during SPS operation with the nominal proton beam for the Large Hadron Collider (LHC). Since the SPS is also part of the heavy-ion injector chain for LHC, dynamic vacuum studies of amorphous carbon films are important to determine their ion induced desorption yields. At the CERN Heavy Ion Accelerator (LINAC 3), carbon-coated accelerator-type stainless steel vacuum chambers were tested for desorption using 4.2 Me...

  11. Heavy-ion induced desorption of a TiZrV coated vacuum chamber bombarded with 5 MeV/u Ar8+ beam at grazing incidence

    International Nuclear Information System (INIS)

    Hedlund, E.; Malyshev, O. B.; Westerberg, L.; Krasnov, A.; Semenov, A. S.; Leandersson, M.; Zajec, B.; Kollmus, H.; Bellachioma, M. C.; Bender, M.; Kraemer, A.; Reich-Sprenger, H.

    2009-01-01

    TiZrV nonevaporable getter (NEG) coated vacuum chambers is a new vacuum technology which is already used in many particle accelerators worldwide. This coating is also of interest for heavy-ion accelerator vacuum chambers. Heavy-ion desorption yields from an activated as well as a CO saturated NEG coated tube have been measured with 5 MeV/u Ar 8+ beam. The sticking probability of the NEG film was obtained by using the partial pressure ratios on two sides of the NEG coated tube. These ratios were compared to results of modeling of the experimental setup with test particle Monte Carlo and angular coefficient methods. The partial pressures inside the saturated NEG coated tube bombarded with heavy ions were up to 20 times larger than those inside the activated one. However, the partial pressure of methane remained the same. The value of the total desorption yield from the activated NEG coated tube is 2600 molecules/ion. The desorption yields after saturation for CH 4 , H 2 , and CO 2 were found to be very close to the yields measured after the activation, while CO increased by up to a factor of 5. The total desorption yield for the saturated tube is up to 7000 molecules/ion. The large value of the desorption yield of the activated NEG coated tube, an order of magnitude higher than the desorption yield from a stainless steel tube at normal incident angle, could be explained by the grazing incident angle

  12. Disordering and amorphization of Zr3Al by 3.8 MeV Zr3+ ion bombardment

    International Nuclear Information System (INIS)

    Chen, F.C.; Ardell, A.J.

    1991-01-01

    The ordered intermetallic compound Zr 3 Al was irradiated with 3. 8 MeV Zr 3+ ions at various fluences up to 5 x 10 12 tons/mm 2 at a temperature of 250 degrees C and the irradiation- induced microstructures were investigated by transmission electron microscopy. Disordering began at the lowest dose, 0.0033 dpa, and complete loss of chemical long-range order occurred at a dose of 0.33 dpa. The onset of amorphization was also observed at this dose. Electron diffraction patterns from irradiated samples showed satellite reflections along in thin foils in [100] orientation and streaking along in foils oriented [011]. These diffraction effects are attributed to the presence of irradiation-induced microstructural defects that, when imaged in dark field, resemble rows of dislocation loops. A model of these arrays of loops, which are suggested to have Burgers vectors of the Frank type, is proposed. The model accounts for the contrast effects observed in the images and the streaking and satellites seen in the diffraction patterns. At the highest dose, 1.6 dpa, a new phase, Zr 5 Al 3 , appeared unexpectedly, most likely as a consequence of irradiation-induced solute segregation

  13. Calculation of ion storage in electron beams with account of ion-ion interactions

    International Nuclear Information System (INIS)

    Perel'shtejn, Eh.A.; Shirkov, G.D.

    1979-01-01

    Ion storage in relativistic electron beams was calculated taking account of ion-ion charge exchange and ionization. The calculations were made for nitrogen ion storage from residual gas during the compression of electron rings in the adhezator of the JINR heavy ion accelerator. The calculations were made for rings of various parameters and for various pressures of the residual gas. The results are compared with analogous calculations made without account of ion-ion processes. It is shown that at heavy loading of a ring by ions ion-ion collisions play a significant part, and they should be taken into account while calculating ion storage

  14. Secondary ion emission from ultra-thin oxide layers bombarded by energetic (MeV) heavy ions: depth of origin and layer homogeneity

    International Nuclear Information System (INIS)

    Allali, H.; Nsouli, B.; Thomas, J.P.; Cabaud, B.; Fuchs, G.; Hoareau, A.; Treilleux, M.; Danel, J.S.

    1993-09-01

    The escape depth of the secondary ions resulting from electronic sputtering of fast heavy ions in inorganic thin films has been investigated. Chromium layers deposited onto SiO 2 substrate as well as SiO x layers deposited onto chromium substrate have been characterized by secondary ion emission mass spectrometry (SIMS) in combination with time-of-flight (TOF) mass analysis (also referred as HSF-SIMS). These crossed experiments lead to a value around 1 nm for SiO x layers and 0.5 nm for Cr layers. On the other hand, HSF-SIMS can be used to correlate the intensity of the secondary ion emission to the film coverage rate and (or) the morphology of particular films like those produced by Low Energy Cluster Beam Deposition (LECBD). Using Sb deposits, the non-linear relationship between ion emission and coverage is interpreted in terms of sputtering enhancement in the individual supported clusters. (author) 22 refs., 9 figs., 1 tab

  15. Electron-impact excitation of molecular ions

    International Nuclear Information System (INIS)

    Neufeld, D.A.; Dalgarno, A.

    1989-01-01

    A simple expression is derived that relates the rate coefficient for dipole-allowed electron-impact excitation of a molecular ion in the Coulomb-Born approximation to the Einstein A coefficient for the corresponding radiative decay. Results are given for several molecular ions of astrophysical interest. A general analytic expression is obtained for the equilibrium rotational level populations in the ground vibrational state of any molecular ion excited by collisions with electrons. The expression depends only upon the electron temperature, the electron density, and the rotational constant of the molecular ion. A similar expression is obtained for neutral polar molecules

  16. An ion-sputtering gun to clean crystal surfaces in-situ in an ultra-high-vacuum electron microscope

    International Nuclear Information System (INIS)

    Morita, Etsuo; Takayanagi, Kunio; Kobayashi, Kunio; Yagi, Katsumichi; Honjo, Goro

    1980-01-01

    The design and performance of an ion-sputtering gun for cleaning crystal surfaces in-situ in an ultra-high-vacuum electron microscope are reported. The electron microscopic aspects of ion-bombardment damage to ionic magnesium oxide, covalent germanium and silicon, and metallic gold and copper crystals, and the effects of annealing after and during sputtering are described. The growth of various kinds of films deposited in-situ on crystals cleaned by ion-sputtering are described and discussed. (author)

  17. Ion emission in solids bombarded with Aun+ (n = 1 - 9) clusters accelerated within the 0.15 - 1.25 MeV energy range

    International Nuclear Information System (INIS)

    Wehbe, Nimer

    2006-06-01

    This experimental work is devoted to the study of the ion emission in solids at the impact of gold clusters of energies within 0.15 to 1.25 MeV range. The physics of ion-solid collisions and the theoretical models of sputtering of solids under ion bombardment are presented in the first chapter. The chapter no. 2 deals with the description of the experimental setup. The study of a gold target allowed to evidence the role of the size and energy of the clusters in determining the emission intensity and the mass distribution of the ions. The 4. chapter gives results from the study of cesium iodide in which the intense emission of CsI clusters could be investigated quantitatively due to multiplicity measurements. Finally, the chapter no. 5 was devoted to the study of a biologic molecule, the phenylalanine, and of a pesticide molecule, chlorosulfuron. This work evidenced the importance of clusters for surface analyses by mass spectrometry

  18. Electron cyclotron resonance discharge as a source for hydrogen and deuterium ions production

    Energy Technology Data Exchange (ETDEWEB)

    Chacon Velasco, A.J. [Universidad de Pamplona, Pamplona (Colombia); Dougar-Jabon, V.D. [Universidad Industrial de Santander, Bucaramanga (Colombia)

    2004-07-01

    In this report, we describe characteristics of a ring-structure hydrogen plasma heated in electron cyclotron resonance conditions and confined in a mirror magnetic trap and discuss the relative efficiency of secondary electrons and thermo-electrons in negative hydrogen and deuterium ion production. The obtained data and calculations of the balance equations for possible reactions demonstrate that the negative ion production is realized in two stages. First, the hydrogen and deuterium molecules are excited in collisions with the plasma electrons to high-laying Rydberg or vibrational levels in the plasma volume. The second stage leads to the negative ion production through the process of dissociative attachment of low energy electrons. The low energy electrons are originated due to a bombardment of the plasma electrode by ions of one of the driven rings and thermo-emission from heated tungsten filaments. Experiments seem to indicate that the negative ion generation occurs predominantly in the limited volume filled with thermo-electrons. Estimation of the negative ion generation rate shows that the main channel of H{sup -} and D{sup -} ion production involves the process of high Rydberg state excitation. (authors)

  19. Electron cyclotron resonance discharge as a source for hydrogen and deuterium ions production

    International Nuclear Information System (INIS)

    Chacon Velasco, A.J.; Dougar-Jabon, V.D.

    2004-01-01

    In this report, we describe characteristics of a ring-structure hydrogen plasma heated in electron cyclotron resonance conditions and confined in a mirror magnetic trap and discuss the relative efficiency of secondary electrons and thermo-electrons in negative hydrogen and deuterium ion production. The obtained data and calculations of the balance equations for possible reactions demonstrate that the negative ion production is realized in two stages. First, the hydrogen and deuterium molecules are excited in collisions with the plasma electrons to high-laying Rydberg or vibrational levels in the plasma volume. The second stage leads to the negative ion production through the process of dissociative attachment of low energy electrons. The low energy electrons are originated due to a bombardment of the plasma electrode by ions of one of the driven rings and thermo-emission from heated tungsten filaments. Experiments seem to indicate that the negative ion generation occurs predominantly in the limited volume filled with thermo-electrons. Estimation of the negative ion generation rate shows that the main channel of H - and D - ion production involves the process of high Rydberg state excitation. (authors)

  20. Suppression of self-organized surface nanopatterning on GaSb/InAs multilayers induced by low energy oxygen ion bombardment by using simultaneously sample rotation and oxygen flooding

    Science.gov (United States)

    Beainy, Georges; Cerba, Tiphaine; Bassani, Franck; Martin, Mickaël; Baron, Thierry; Barnes, Jean-Paul

    2018-05-01

    Time of flight secondary ion mass spectrometry (ToF-SIMS) is a well-adapted analytical method for the chemical characterization of concentration profiles in layered or multilayered materials. However, under ion beam bombardment, initially smooth material surface becomes morphologically unstable. This leads to abnormal secondary ion yields and depth profile distortions. In this contribution, we explore the surface topography and roughening evolution induced by O2+ ion bombardment on GaSb/InAs multilayers. We demonstrate the formation of nanodots and ripples patterning according to the ion beam energy. Since the latter are undesirable for ToF-SIMS analysis, we managed to totally stop their growth by using simultaneously sample rotation and oxygen flooding. This unprecedented coupling between these two latter mechanisms leads to a significant enhancement in depth profiles resolution.

  1. Ion accumulation and space charge neutralization in intensive electron beams for ion sources and electron cooling

    International Nuclear Information System (INIS)

    Shirkov, G.D.

    1996-01-01

    The Electron Beam Ion Sources (EBIS), Electron Beam Ion Traps (EBIT) and electron beams for electron cooling application have the beam parameters in the same ranges of magnitudes. EBIS and EBIT produce and accumulate ions in the beam due to electron impact ionization. The cooling electron beam accumulates positive ions from the residual gas in the accelerator chamber during the cooling cycle. The space charge neutralization of cooling beam is also used to reduce the electron energy spread and enhance the cooling ability. The advanced results of experimental investigations and theoretical models of the EBIS electron beams are applied to analyze the problem of beam neutralization in the electron cooling techniques. The report presents the analysis of the most important processes connected with ion production, accumulation and losses in the intensive electron beams of ion sources and electron cooling systems for proton and ion colliders. The inelastic and elastic collision processes of charged particles in the electron beams are considered. The inelastic processes such as ionization, charge exchange and recombination change the charge states of ions and neutral atoms in the beam. The elastic Coulomb collisions change the energy of particles and cause the energy redistribution among components in the electron-ion beams. The characteristic times and specific features of ionization, beam neutralization, ion heating and loss in the ion sources and electron cooling beams are determined. The dependence of negative potential in the beam cross section on neutralization factor is studied. 17 refs., 5 figs., 1 tab

  2. Electron capture in ion atom and ion-ion collisions

    International Nuclear Information System (INIS)

    Barat, M.

    1986-01-01

    Electron capture (EC) by positive ions in collision with various targets has remained one of the most important subjects of research since the early 30's. From a theoretical point of view, EC is obviously a coupled 3-body problem: at least two cores and an active electron that jumps between them. Practical interest in EC arose in a variety of fields. Recently a renewed interest arose from the physics of thermonuclear fusion, where capture by highly charged ionic impurities were found to be an important process in tokamak devices. For that reasons, a number of reviews were devoted to this subject during the past years, including lectures given in various NATO advanced science institutes. The aim of this lecture is not at all to add a new review to this list, but (i) to summarize the very basis of the present theoretical approaches at low and moderate collision energy, (ii) to pinpoint some crucial difficulties in the theoretical treatment, (iii) to select specific examples which, to the taste of the author, reflect some present practical interest, or some significant advances. 48 references, 38 figures, 1 table

  3. Measurement of ion species produced due to bombardment of 450 eV N{sub 2}{sup +} ions with hydrocarbons-covered surface of tungsten: Formation of tungsten nitride

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India); Bhatt, P. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kumar, A. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Singh, B.K.; Singh, B.; Prajapati, S. [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India); Shanker, R., E-mail: shankerorama@gmail.com [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India)

    2016-08-01

    A laboratory experiment has been performed to study the ions that are produced due to collisions of 450 eV N{sub 2}{sup +} ions with a hydrocarbons-covered surface of polycrystalline tungsten at room temperature. Using a TOF mass spectrometry technique, the product ions formed in these collisions have been detected, identified and analyzed. Different ion–surface reaction processes, namely, neutralization, reflection, surface induced dissociation, surface induced chemical reactions and desorption are observed and discussed. Apart from the presence of desorbed aliphatic hydrocarbon and other ions, the mass spectra obtained from the considered collisions show the formation and sputtering of tungsten nitride (WN). A layer of WN on tungsten surface is known to decrease the sputtering of bulk tungsten in fusion devices more effectively than when the tungsten is bombarded with other seeding gases (He, Ar). It is further noted that there is a negligible diffusion of N in the bulk tungsten at room temperature.

  4. A compact CMA spectrometer with axially integrated hybrid electron-ion gun for ISS, AES and sputter depth profile analysis

    International Nuclear Information System (INIS)

    Gisler, E.; Bas, E.B.

    1986-01-01

    Until now, the combined application of electrons and ions in surface analysis required two separate sources for electrons and ions with different incidence angles. The newly developed hybrid electron-ion gun, however, allows bombardment of the same sample area both with noble gas ions and with electrons coming from the same direction. By integrating such a hybrid gun axially in a cylindrical mirror energy analyser (CMA) a sensitive compact single flange spectrometer obtains for ion scattering spectroscopy (ISS), Auger electron spectroscopy (AES), and sputtering all within normal beam incidence. This concept makes accurate beam centering very easy. Additionally, the bombardment from the same direction both for sputtering and for surface analysis brings advantages in depth profiling. The scattering angle for ISS has a constant value of about 138 0 . The hybrid gun delivers typically an electron beam current of -20μA at 3keV for AES, and an ion beam current of +40 nA and +1.2μA at 2 keV for ISS and sputtering respectively. The switching time between ISS, AES, and sputtering mode is about 0.1 s. So this system is best suited for automatically controlled depth profile analysis. The design and operation of this new system will be described and some applications will be discussed. (author)

  5. Study of the machining of uranium carbide rods obtained by continuous casting under electronic bombardment; Etude de l'usinage de barreaux de carbure d'uranium obtenus par coulee continue sous bombardement electronique

    Energy Technology Data Exchange (ETDEWEB)

    Rousset, P.; Accary, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The authors consider the various methods of machining uranium mono-carbide and compare them critically in the case of their application to uranium carbide obtained by fusion under an electronic bombardment and continuous casting. This study leads them to propose two mechanical machining methods: cylindrical rectification and center-less rectification, preceded by a preliminary roughing out of a cylinder, the latter appearing more suitable. A study of the machining yields as a function of the diameter of the rough bars and of the diameter of the finished rods has shown that an optimum value of the rough bar diameter exists for each value of the finished rod diameter. It is found that the yield increases as the diameter itself increases, this yield rising from 45 per cent to around 70 per cent as the diameter of the rough bars increases from 25-26 mm to 37-38 mm. (authors) [French] Les auteurs envisagent les differentes methodes d'usinage du monocarbure d'uranium et se livrent a une etude critique de celles-ci, dans le cas de leur application a l'usinage de barreaux de carbure d'uranium obtenus par fusion sous bombardement electronique et coulee continue. Cette etude les conduit a proposer deux methodes d'usinage mecanique: la rectification cylindrique et la rectification 'centerless', precedee d'un ebauchage par carottage, la seconde paraissant la plus appropriee. L'etude des rendements d'usinage en fonction du diametre des barreaux bruts et du diametre des barreaux finis, a mis en evidence une valeur optimale du diametre des barreaux bruts pour chaque valeur du diametre des barreaux usines. Elle a montre que le rendement croit lorsque le diametre croit lui-meme, ce rendement passant d'environ 45 pour cent a environ 70 pour cent, lorsque le diametre des barreaux bruts passe de 25-26 mm a 37-38 mm.

  6. Electron cyclotron resonance multiply charged ion sources

    International Nuclear Information System (INIS)

    Geller, R.

    1975-01-01

    Three ion sources, that deliver multiply charged ion beams are described. All of them are E.C.R. ion sources and are characterized by the fact that the electrons are emitted by the plasma itself and are accelerated to the adequate energy through electron cyclotron resonance (E.C.R.). They can work without interruption during several months in a quasi-continuous regime. (Duty cycle: [fr

  7. Electrical properties of irradiated PVA film by using ion/electron beam

    Science.gov (United States)

    Abdelrahman, M. M.; Osman, M.; Hashhash, A.

    2016-02-01

    Ion/electron beam bombardment has shown great potential for improving the surface properties of polymers. Low-energy charged (ion/electron) beam irradiation of polymers is a good technique to modify properties such as electrical conductivity, structural behavior, and their mechanical properties. This paper reports on the effect of nitrogen and electron beam irradiation on the electrical properties of polyvinyl alcohol (PVA) films. PVA films of 4 mm were exposed to a charged (ion/electron) beam for different treatment times (15, 30, and 60 minutes); the beam was produced from a dual beam source using nitrogen gas with the other ion/electron source parameters optimized. The dielectric loss tangent tan δ , electrical conductivity σ , and dielectric constant ɛ ^' } in the frequency range 100 Hz-100 kHz were measured at room temperature. The variation of dielectric constant and loss tangent as a function of frequency was also studied at room temperature. The dielectric constant was found to be strongly dependent on frequency for both ion and electron beam irradiation doses. The real (ɛ ^' }) and imaginary (ɛ ^' ' }) parts of the dielectric constant decreased with frequency for all irradiated and non-irradiated samples. The AC conductivity showed an increase with frequency for all samples under the influence of both ion and electron irradiation for different times. Photoluminescence (PL) spectral changes were also studied. The formation of clusters and defects (which serve as non-radiative centers on the polymer surface) is confirmed by the decrease in the PL intensity.

  8. Study of electron beam effects on surfaces using x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS)

    International Nuclear Information System (INIS)

    Gettings, M.; Coad, J.P.

    1976-02-01

    Discrepancies in the surface analyses of oxidised or heavily contaminated materials have been observed between X-ray Photoelectron Spectroscopy (XPS) and techniques using electron beams (primarily Auger Electron Spectroscopy (AES)). These discrepancies can be ascribed to the influence of the primary electron beam and to illustrate the various types of electron effects different materials were analysed using XPS and Secondary Ion Mass Spectroscopy (SIMS) before and after large area electron bombardment. The materials used included chrome and stainless steels, nickel, platinum, glass and brass. (author)

  9. ECR ion source with electron gun

    Science.gov (United States)

    Xie, Zu Q.; Lyneis, Claude M.

    1993-01-01

    An Advanced Electron Cyclotron Resonance ion source (10) having an electron gun (52) for introducing electrons into the plasma chamber (18) of the ion source (10). The ion source (10) has a injection enclosure (12) and a plasma chamber tank (14). The plasma chamber (18) is defined by a plurality of longitudinal magnets (16). The electron gun (52) injects electrons axially into the plasma chamber (18) such that ionization within the plasma chamber (18) occurs in the presence of the additional electrons produced by the electron gun (52). The electron gun (52) has a cathode (116) for emitting electrons therefrom which is heated by current supplied from an AC power supply (96) while bias potential is provided by a bias power supply (118). A concentric inner conductor (60) and Outer conductor (62) carry heating current to a carbon chuck (104) and carbon pusher (114) Which hold the cathode (116) in place and also heat the cathode (16). In the Advanced Electron Cyclotron Resonance ion source (10), the electron gun (52) replaces the conventional first stage used in prior art electron cyclotron resonance ion generators.

  10. Doubly versus Singly Positively Charged Oxygen Ions Back-Scattering from a Silicon Surface under Dynamic O2+ Bombardment

    Czech Academy of Sciences Publication Activity Database

    Franzreb, K.; Williams, P.; Lörinčík, Jan; Šroubek, Zdeněk

    203-204, 1/4 (2003), s. 39-42 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z2067918; CEZ:AV0Z4040901 Keywords : low-energy ion scattering * doubly charged ions * molecular orbital Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.284, year: 2003

  11. Programme and abstracts of the seventh International Conference on Ion Implantation and other Applications of Ions and Electrons (ION 2008)

    International Nuclear Information System (INIS)

    2008-01-01

    The conference is organized on the biennial basis by the Institute of Physics, Maria Curie-Sklodowska University, Lublin in cooperation with the Wroclaw University of Technology and Technical University of Lublin. This biennial conferences has created a unique opportunity for scientists from Eastern and Western Europe together with their Polish colleagues, to discuss in a most agreeable environment, some of the fundamental questions in their field and develop new perspectives through the mutual exchange of ideas. ION 2008 has been focused mainly on ion implantation, a powerful tool for the modification of the subsurface layers of solid materials. Although the technique has been in use in the electronic industry for a few decades, there still remain many phenomena involved in the implantation process that are not well understood and are of considerable interest, for both fundamental science and also for new developments in applied materials science. One can highlight, in particular, mechanisms of ion energy loss in the bombarded material, creation of radiation defects, the formation of latent tracks, and many other phenomena that researchers are now intensively investigating. An improved understanding of such processes is essential for the effective application of analytical techniques like RBS, ERD, SIMS, PIPE and others

  12. Proposed LLNL electron beam ion trap

    International Nuclear Information System (INIS)

    Marrs, R.E.; Egan, P.O.; Proctor, I.; Levine, M.A.; Hansen, L.; Kajiyama, Y.; Wolgast, R.

    1985-01-01

    The interaction of energetic electrons with highly charged ions is of great importance to several research fields such as astrophysics, laser fusion and magnetic fusion. In spite of this importance there are almost no measurements of electron interaction cross sections for ions more than a few times ionized. To address this problem an electron beam ion trap (EBIT) is being developed at LLNL. The device is essentially an EBIS except that it is not intended as a source of extracted ions. Instead the (variable energy) electron beam interacting with the confined ions will be used to obtain measurements of ionization cross sections, dielectronic recombination cross sections, radiative recombination cross sections, energy levels and oscillator strengths. Charge-exchange recombinaion cross sections with neutral gasses could also be measured. The goal is to produce and study elements in many different charge states up to He-like xenon and Ne-like uranium. 5 refs., 2 figs

  13. Ion acceleration in modulated electron beams

    International Nuclear Information System (INIS)

    Bonch-Osmolovskij, A.G.; Dolya, S.N.

    1977-01-01

    A method of ion acceleration in modulated electron beams is considered. Electron density and energy of their rotational motion are relatively low. However the effective ion-accelerating field is not less than 10 MeV/m. The electron and ion numbers in an individual bunch are also relatively small, although the number of produced bunches per time unit is great. Some aspects of realization of the method are considered. Possible parameters of the accelerator are given. At 50 keV electron energy and 1 kA beam current a modulation is realized at a wave length of 30 cm. The ion-accelerating field is 12 MeV/m. The bunch number is 2x10 3 in one pulse at a gun pulse duration of 2 μs. With a pulse repetition frequency of 10 2 Hz the number of accelerated ions can reach 10 13 -10 14 per second

  14. Net sputtering rate due to hot ions in a Ne-Xe discharge gas bombarding an MgO layer

    International Nuclear Information System (INIS)

    Ho, S.; Tamakoshi, T.; Ikeda, M.; Mikami, Y.; Suzuki, K.

    2011-01-01

    An analytical method is developed for determining net sputtering rate for an MgO layer under hot ions with low energy ( h i , above a threshold energy of sputtering, E th,i , multiplied by a yield coefficient. The threshold energy of sputtering is determined from dissociation energy required to remove an atom from MgO surface multiplied by an energy-transfer coefficient. The re-deposition rate of the sputtered atoms is calculated by a diffusion simulation using a hybridized probabilistic and analytical method. These calculation methods are combined to analyze the net sputtering rate. Maximum net sputtering rate due to the hot neon ions increases above the partial pressure of 4% xenon as E h Ne becomes higher and decreases near the partial pressure of 20% xenon as ion flux of neon decreases. The dependence due to the hot neon ions on partial pressure and applied voltage agrees well with experimental results, but the dependence due to the hot xenon ions deviates considerably. This result shows that the net sputtering rate is dominated by the hot neon ions. Maximum E h Ne (E h Ne,max = 5.3 - 10.3 eV) is lower than E th,Ne (19.5 eV) for the MgO layer; therefore, weak sputtering due to the hot neon ions takes place. One hot neon ion sputters each magnesium and each oxygen atom on the surface and distorts around a vacancy. The ratio of the maximum net sputtering rate is approximately determined by number of the ions at E h i,max multiplied by an exponential factor of -E th,i /E h i,max .

  15. Electron string ion sources for carbon ion cancer therapy accelerators

    Science.gov (United States)

    Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Katagiri, K.; Noda, K.; Ponkin, D. O.; Ramzdorf, A. Yu.; Salnikov, V. V.; Shutov, V. B.

    2015-08-01

    The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C4+ and C6+ ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 1010 C4+ ions per pulse and about 5 × 109 C6+ ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 1011 C6+ ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the 11C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C4+ ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of 11C, transporting to the tumor with the primary accelerated 11C4+ beam, this efficiency is preliminarily considered to be large enough to produce the 11C4+ beam from radioactive methane and to inject this beam into synchrotrons.

  16. Effect of radical species density and ion bombardment during ashing of extreme ultralow-κ interlevel dielectric materials

    International Nuclear Information System (INIS)

    Worsley, M. A.; Bent, S. F.; Fuller, N. C. M.; Tai, T. L.; Doyle, J.; Rothwell, M.; Dalton, T.

    2007-01-01

    The significance of ion impact and radical species density on ash-induced modification of an extreme ultralow-κ interlevel dielectric (ILD) material (κ 2 and Ar/N 2 dual frequency capacitive discharges is determined by combining plasma diagnostics, modeling of the ion angular distribution function, and material characterization such as angle resolved x-ray photoelectron spectroscopy. Radical species density was determined by optical emission actinometry under the same conditions and in the same reactor in a previous study by the present authors. ILD modification is observed and correlated with changes in the plasma for a range of pressures (5-60 mTorr), bias powers (0-350 W), and percent Ar in the source gas (0%, 85%). For the Ar/O 2 discharge, extensive modification of the ILD sidewall was observed for significant ion scattering conditions, whereas minimal modification of the ILD sidewall was observed under conditions of minimal or no ion scattering. Further, for an identical increase in the O-radical density (∼ an order of magnitude), a different degree of modification was induced at the ILD trench bottom surface depending on whether pressure or percent Ar was used to increase the radical density. The different degrees of modification seemingly correlated with the relative changes in the ion current for increasing pressure or percent Ar. For the Ar/N 2 discharge, reduced damage of the ILD sidewall and trench bottom surfaces was observed for increasing pressure (increasing N-radical density) and decreasing ion current to both surfaces. It is, thus, proposed that the mechanism for modification of the porous ILD is dominated by the creation of reactive sites by ion impact under the present conditions. A detailed discussion of the results which support this proposal is presented

  17. Electron-cyclotron-resonance ion sources (review)

    International Nuclear Information System (INIS)

    Golovanivskii, K.S.; Dougar-Jabon, V.D.

    1992-01-01

    The physical principles are described and a brief survey of the present state is given of ion sources based on electron-cyclotron heating of plasma in a mirror trap. The characteristics of ECR sources of positive and negative ions used chiefly in accelerator technology are presented. 20 refs., 10 figs., 3 tabs

  18. Ion beam processing of advanced electronic materials

    International Nuclear Information System (INIS)

    Cheung, N.W.; Marwick, A.D.; Roberto, J.B.

    1989-01-01

    This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases

  19. Role of Ion Bombardment, Film Thickness and Temperature of Annealing on PEC Activity of Very-thin Film Hematite .

    Czech Academy of Sciences Publication Activity Database

    Kment, Š.; Čada, M.; Hubička, Z.; Krýsa, J.; Kmentová, Hana; Olejníček, J.; Zlámalová Cílová, Z.; Zbořil, R.

    2016-01-01

    Roč. 41, č. 27 (2016), s. 11547-11557 ISSN 0360-3199. [International Conference on Hydrogen Energy /1./. Aveiro, 20.07.2015-22.07.2015] Institutional support: RVO:67985858 Keywords : ion flux density * hematite photoanode * thin films Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.582, year: 2016

  20. Materials surface modification by plasma bombardment under simultaneous erosion and redeposition conditions

    International Nuclear Information System (INIS)

    Hirooka, Y.; Goebel, D.M.; Conn, R.W.

    1986-07-01

    The first in-depth investigation of surface modification of materials by continuous, high-flux argon plasma bombardment under simultaneous erosion and redeposition conditions have been carried out for copper and 304 stainless steel using the PISCES facility. The plasma bombardment conditions are: incident ion flux range from 10 17 to 10 19 ions sec -1 cm -2 , total ion fluence is controlled between 10 19 and 10 22 ions cm -2 , electron temperature range from 5 to 15 eV, and plasma density range from 10 11 to 10 13 cm -3 . The incident ion energy is 100 eV. The sample temperature is between 300 and 700K. Under redeposition dominated conditions, the material erosion rate due to the plasma bombardment is significantly smaller (by a factor up to 10) than that can be expected from the classical ion beam sputtering yield data. It is found that surface morphologies of redeposited materials strongly depend on the plasma bombardment condition. The effect of impurities on surface morphology is elucidated in detail. First-order modelings are implemented to interpret the reduced erosion rate and the surface evolution. Also, fusion related surface properties of redeposited materials such as hydrogen reemission and plasma driven permeation have been characterized

  1. Effects of MeV Si ions bombardment on the thermoelectric generator from SiO{sub 2}/SiO{sub 2} + Cu and SiO{sub 2}/SiO{sub 2} + Au nanolayered multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Budak, S., E-mail: satilmis.budak@aamu.edu [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Chacha, J., E-mail: chacha_john79@hotmail.com [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Smith, C., E-mail: cydale@cim.aamu.edu [Center for Irradiation of Materials, Alabama A and M University, Normal, AL (United States); Department of Physics, Alabama A and M University, Normal, AL (United States); Pugh, M., E-mail: marcuspughp@yahoo.com [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Colon, T. [Department of Mechanical Engineering, Alabama A and M University, Normal, AL (United States); Heidary, K., E-mail: kaveh.heidary@aamu.edu [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Johnson, R.B., E-mail: barry@w4wb.com [Department of Physics, Alabama A and M University, Normal, AL (United States); Ila, D., E-mail: ila@cim.aamu.edu [Center for Irradiation of Materials, Alabama A and M University, Normal, AL (United States); Department of Physics, Alabama A and M University, Normal, AL (United States)

    2011-12-15

    The defects and disorder in the thin films caused by MeV ions bombardment and the grain boundaries of these nanoscale clusters increase phonon scattering and increase the chance of an inelastic interaction and phonon annihilation. We prepared the thermoelectric generator devices from 100 alternating layers of SiO{sub 2}/SiO{sub 2} + Cu multi-nano layered superlattice films at the total thickness of 382 nm and 50 alternating layers of SiO{sub 2}/SiO{sub 2} + Au multi-nano layered superlattice films at the total thickness of 147 nm using the physical vapor deposition (PVD). Rutherford Backscattering Spectrometry (RBS) and RUMP simulation have been used to determine the stoichiometry of the elements of SiO{sub 2}, Cu and Au in the multilayer films and the thickness of the grown multi-layer films. The 5 MeV Si ions bombardments have been performed using the AAMU-Center for Irradiation of Materials (CIM) Pelletron ion beam accelerator to make quantum (nano) dots and/or quantum (quantum) clusters in the multilayered superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardments we have measured Seebeck coefficient, cross-plane electrical conductivity, and thermal conductivity in the cross-plane geometry for different fluences.

  2. Neutron radiation field due to 6.6 MeV/amu 58Ni ions bombarding a thick Cu target

    International Nuclear Information System (INIS)

    Aleinikov, V.E.; Cherevatenko, A.P.; Clapier, F.B.; Tsovbun, V.I.

    1985-01-01

    The angular distribution of the dose equivalent rate and neutron spectra were obtained using the Bonner sphere spectrometry method. The quality factor was measured by a tissue-equivalent Rem-2 chamber at several angles. The agreement between the results of the measurements and an empirical parameterisation of the angular distribution is satisfactory. The total yield is estimated to be 1.6+-0.4x10 -3 neutrons per heavy ion. (author)

  3. Electron cyclotron resonance (E.C.R.) multiply charged ion sources

    International Nuclear Information System (INIS)

    Geller, R.

    1978-01-01

    High charge state ions can be produced by electron bombardment inside targets when the target electron density n (cm -3 ) multiplied by the ion transit time through the target tau (sec) is: n tau > 5.10 9 cm -3 sec. The relative velocity between electrons and ions determines the balance between stripping and capture i.e. the final ion charge state. (In a stripper foil fast ions interact with slow electrons involving typically n approximately 10 24 cm -3 , tau approximately 10 -14 sec). In the E.C.R. source a cold ion plasma created in a first stage diffuses slowly through a second stage containing a hot E.C.R. plasma with n > 3.10 11 cm -3 and tau > 10 -2 sec. Continuous beams of several μA of C 6+ N 7+ Ne 9+ A 11+ are extracted from the second stage with normalized emittances of approximately 0.5 π mm mrad. The absence of cathodes and plasma arcs makes the source very robust, reliable and well-fitted for cyclotron injection. A super conducting source is under development

  4. Electronic stopping in ion-fullerene collisions

    NARCIS (Netherlands)

    Schlathölter, T.A.; Hadjar, O.; Hoekstra, R.A.; Morgenstern, R.W.H.

    The electronic friction experienced by a multiply charged ion interacting with the valence electrons of a single fullerene is an important aspect of the collision dynamics. It manifests itself in a considerable loss of projectile kinetic energy transferred to the target, resulting in excitation. The

  5. Indirect processes in electron-ion scattering

    International Nuclear Information System (INIS)

    Bottcher, C.; Griffin, D.C.; Pindzola, M.S.; Phaneuf, R.A.

    1983-10-01

    A summary is given of an informal workshop held at Oak Ridge National Laboratory on June 22-23, 1983, in which the current status of theoretical calculations of indirect processes in electron-ion scattering was reviewed. Processes of particular interest in astrophysical and fusion plasmas were emphasized. Topics discussed include atomic structure effects, electron-impact ionization, and dielectronic recombination

  6. Indirect processes in electron-ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bottcher, C.; Griffin, D.C.; Pindzola, M.S.; Phaneuf, R.A.

    1983-10-01

    A summary is given of an informal workshop held at Oak Ridge National Laboratory on June 22-23, 1983, in which the current status of theoretical calculations of indirect processes in electron-ion scattering was reviewed. Processes of particular interest in astrophysical and fusion plasmas were emphasized. Topics discussed include atomic structure effects, electron-impact ionization, and dielectronic recombination.

  7. Electron detachment in ion-atom collisions

    International Nuclear Information System (INIS)

    Vreugd, C. de.

    1980-01-01

    The electron detachment process that occurs in negative ion-atom collisions is investigated. Differential cross sections were measured for the collisions of F - , Cl - , Br - , I - on He, Ne, Ar, Kr, Xe, Na and K. Electron energy distributions were obtained for some of the systems. (Auth.)

  8. Electron string ion sources for carbon ion cancer therapy accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ponkin, D. O.; Ramzdorf, A. Yu.; Salnikov, V. V.; Shutov, V. B. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Katagiri, K.; Noda, K. [National Institute of Radiological Science, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2015-08-15

    The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C{sup 4+} and C{sup 6+} ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 10{sup 10} C{sup 4+} ions per pulse and about 5 × 10{sup 9} C{sup 6+} ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 10{sup 11} C{sup 6+} ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the {sup 11}C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C{sup 4+} ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of {sup 11}C, transporting to the tumor with the primary accelerated {sup 11}C{sup 4+} beam, this efficiency is preliminarily considered to be large enough to produce the {sup 11}C{sup 4+} beam from radioactive methane and to inject this beam into synchrotrons.

  9. Damage of niobium surfaces caused by bombardment with 4He+ ions of different energies typical for T-20

    International Nuclear Information System (INIS)

    Guseva, M.I.; Gusev, V.; Martynenko, Yu.V.; Das, S.K.; Kaminsky, M.

    1979-01-01

    The aim of the present studies was to study surface damage due to blistering of both annealed and cold-worked niobium (a candidate first wall material for keV) irradiated sequentially with 4 He + ions with energies of 0.5 to 1800 keV for a total dose of 5.0 C/cm 2 . A typical surface of cold-worked Nb after irradiations with 4 He + ions with increasing energy from 0.5 to 90 keV is shown. The blister diameters range from 0.1 μm to 3 μm, and most of the blisters have exfoliated. The blisters fall into several size classes, the two most dominant ones having most probable blister diameters of approx. 0.27 μm and approx. 2.0 μm. The skin thickness of the larger blisters was measured to be approx. 0.23 μm. Also shown is the same area after irradiation with 150-1800-keV 4 He + irradiation for a dose of 0.66 C/cm 2 . A few additional blisters can be seen. A cold-worked Nb surface that was irradiated only with 150-1800-keV 4 He + ions is also shown. It is seen that prior irradiation with 0.5-90-keV 4 He + helped in significantly reducing blistering. For a total dose of 0.5 C/cm 2 , the erosion yield due to helium blistering of Nb ranges from (5.4 +- 2.0) x 10 -3 to (1.5 +- 0.7) x 10 -2 atoms/ion. For the cold-worked Nb target the results indicate clearly that the 4 He + implantations for the energy range from 0.5 to 90 keV help to reduce both the density and diameter of blisters formed by subsequent He-implantation for the energy ranging from 150 to 1800 keV. 2 figures

  10. Effect of Carbon Concentration on the Sputtering of Carbon-Rich SiC Bombarded by Helium Ions

    Directory of Open Access Journals (Sweden)

    Xinghao Liang

    2018-02-01

    Full Text Available Silicon carbide (SiC is considered as an important material for nuclear engineering due to its excellent properties. Changing the carbon content in SiC can regulate and control its elastic and thermodynamic properties, but a simulation study of the effect of carbon content on the sputtering (caused by the helium ions of SiC is still lacking. In this work, we used the Monte-Carlo and molecular dynamics simulation methods to study the effects of carbon concentration, incidence energy, incident angle, and target temperature on the sputtering yield of SiC. The results show that the incident ions’ energy and angle have a significant effect on sputtering yield of SiC when the carbon concentration in SiC is around 62 at %, while the target temperature has a little effect on the sputtering yield of SiC. Our work might provide theoretical support for the experimental research and engineering application of carbon fiber-reinforced SiC that be used as the plasma-facing material in tokamak fusion reactors.

  11. Electron spectroscopy with fast heavy ions

    International Nuclear Information System (INIS)

    Schneider, D.

    1983-01-01

    Since about 1970 the spectroscopy of Auger-electrons and characteristic x-rays following energetic ion-atom collisions has received a great deal of attention. An increasing number of accelerators, capable of providing a large number of projectile ion species over a wide range of projectile energies, became available for studying ion-atom collision phenomena. Many charged particles from protons up to heavy ions like uranium can be accelerated to energies ranging over six orders of magnitude. This allows us to study systematically a great variety of effects accompanied by dynamic excitation processes of the atomic shells in either the projectile- or target-atoms. The studies yield fundamental information regarding the excitation mechanism (e.g., Coulomb and quasi-molecular excitation) and allow sensitive tests of atomic structure theories. This information in turn is valuable to other fields in physics like plasma-, astro-, or solid-state (surface) physics. It is a characteristic feature of fast heavy-ion accelerators that they can produce highly stripped ion species which have in turn the capability to highly ionize neutral target atoms or molecules in a single collision. The ionization process, mainly due to the strong electrical fields that are involved, allows us to study few-electron atoms with high atomic numbers Z. High resolution spectroscopy performed with these atoms allows a particularly good test of relativistic and QED effects. The probability of producing these few electron systems is determined by the charge state and the velocity of the projectile ions. In this contribution the possibilities of using electron spectroscopy as a tool to investigate fast ion-atom collisions is discussed and demonstrated with a few examples. 30 references

  12. Ranges, Reflection and Secondary Electron Emission for keV Hydrogen Ions Incident on Solid N2

    DEFF Research Database (Denmark)

    Børgesen, P.; Sørensen, H.; Hao-Ming, Chen

    1983-01-01

    Ranges were measured for 0.67–3.3 keV/amu hydrogen and deuterium ions in solid N2. Comparisons with similar results for N2-gas confirm the previously observed large phase effect in the stopping cross section. Measurements of the secondary electron emission coefficient for bulk solid N2 bombarded...... by 0.67–9 keV/amu ions also seem to support such a phase effect. It is argued that we may also extract information about the charge state of reflected projectiles....

  13. Radiative electron capture by channeled ions

    International Nuclear Information System (INIS)

    Pitarke, J.M.; Ritchie, R.H.; Tennessee Univ., Knoxville, TN

    1989-01-01

    Considerable experimental data have been accumulated relative to the emission of photons accompanying electron capture by swift, highly stripped atoms penetrating crystalline matter under channeling conditions. Recent data suggest that the photon energies may be less than that expected from simple considerations of transitions from the valence band of the solid to hydrogenic states on the moving ion. We have studied theoretically the impact parameter dependence of the radiative electron capture (REC) process, the effect of the ion's wake and the effect of capture from inner shells of the solid on the photon emission probability, using a statistical approach. Numerical comparisons of our results with experiment are made. 13 refs., 6 figs

  14. Emission of low-energetic electrons in collisions of heavy ions with solid targets

    International Nuclear Information System (INIS)

    Lineva, Natallia

    2008-07-01

    At the UNILAC accelerator, we have initiated a project with the objective to investigate lowenergy electrons, emitted from solid, electrically conductive targets after the impact of swift light and heavy ions. For this purposes, we have installed, optimized, and put into operation an electrostatic toroidal electron spectrometer. First, investigations of electrons, emitted from solid-state targets after the bombardment with a monochromatic electron beam from an electron gun, has been carried out. The proposed method combines the results of the measurements with the results of dedicated Monte Carlo simulations. The method has been elaborated in a case study for carbon targets. The findings have been instrumental for the interpretation of our measurements of electrons emitted in collisions of swift ions with the same carbon targets. Our investigations focused on following ion beams: protons and (H + 3 )-molecules of the same energy, as well as on carbon ions with two different energies. Thin carbon, nickel, argon and gold foils has been used as targets. Electrons in the energy range between 50 eV and 1 keV have been investigated. The measured electron distributions, both integral as well as differential with respect to the polar angle, have been compared to simple standard theories for gases as well as to the results of TRAX simulations, the latter being based on data from gaseous targets. Dedicated TRAX simulations have been performed only for the carbon targets, applying the method mentioned above. Within our experimental uncertainties, we observe a good agreement of the measured and TRAX simulated data. That leads us to the conclusion that - as a first order approximation - the electron emission pattern from ion-atom collisions in solid-state targets and the one from single collisions in gases are similar. (orig.)

  15. Ion-acoustic solitons in a plasma with electron beam

    International Nuclear Information System (INIS)

    Esfandyari, A. R.; Khorram, S.

    2001-01-01

    Ion-acoustic solitons in a collisionless plasma consisting of warm ions, hot isothermal electrons and a electron beam are studied by using the reductive perturbation method. The basic set of fluid equations is reduced to Korteweg-de Vries and modified Korteweg-de Vries temperature and electron beam on ion acoustic equations. The effect of ion solitons are investigated

  16. The generation of intense heat fluxes by electron bombardment to evaluate the use of swirl flow in the cooling of accelerator targets

    International Nuclear Information System (INIS)

    Genis, G.J.

    1985-11-01

    The thermal performance of isotope production targets for accelerators has been shown to be the limiting factor with regard to the cost of isotopes and the specific activity achievable. To allow the investigation of basic aspects of target cooling and the evaluation of certain target concepts off-line from accelerators, an electron bombardment system, including a radial electron accelerator (REA) in a diode configuration, was developed as heat source. Methods were developed to characterise the performance of the REA to supply a homogeneous heat flux to an axial target by which a technique for the construction of thermocouple placement holes in the body of the target can be evaluated from the measured temperatures. Having identified high velocity swirl flow as the most suitable technique to enhance the convective heat transfer in targets, experiments were conducted to determine the heat-transfer coefficient at high heat fluxes to high velocity swirl flow. The heat-transfer results substantiate the advantages of swirl flow for target cooling. Different correlations obtained indicate the importance of using the film properties instead of the bulk coolant properties in correlations and identify centrifugal convection as one of the most important heat transfer mechanisms in swirl flow

  17. Calculation of energy and angular distributions of the bremsstrahlung of 10 MeV electrons bombarding a thick tungsten target

    International Nuclear Information System (INIS)

    Tsovbun, V.I.

    1977-01-01

    Computer calculations have been performed to extend the data available on energy and angular distribution of the 10 MeV electron bremsrahlung into a higher angle region. The ETRAN-16D program developed by R.G.Berger for calculation of electron-photon cascades passing through matter using computers IBM-360 and UNIVAC-1108 was modified to operate with the CDC-6500 computer. A brief summary of the program is provided. An angular distribution of the bremsstrahlung dose absorbed in the air has been also calculated. The results extended into the 90-180 deg region can be used to calculate the biological shield of electron accelerators

  18. A Monte Carlo simulation code for calculating damage and particle transport in solids: The case for electron-bombarded solids for electron energies up to 900 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qiang [College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001 (China); Shao, Lin, E-mail: lshao@tamu.edu [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States)

    2017-03-15

    Current popular Monte Carlo simulation codes for simulating electron bombardment in solids focus primarily on electron trajectories, instead of electron-induced displacements. Here we report a Monte Carol simulation code, DEEPER (damage creation and particle transport in matter), developed for calculating 3-D distributions of displacements produced by electrons of incident energies up to 900 MeV. Electron elastic scattering is calculated by using full-Mott cross sections for high accuracy, and primary-knock-on-atoms (PKAs)-induced damage cascades are modeled using ZBL potential. We compare and show large differences in 3-D distributions of displacements and electrons in electron-irradiated Fe. The distributions of total displacements are similar to that of PKAs at low electron energies. But they are substantially different for higher energy electrons due to the shifting of PKA energy spectra towards higher energies. The study is important to evaluate electron-induced radiation damage, for the applications using high flux electron beams to intentionally introduce defects and using an electron analysis beam for microstructural characterization of nuclear materials.

  19. Electron-ion-x-ray spectrometer system

    International Nuclear Information System (INIS)

    Southworth, S.H.; Deslattes, R.D.; MacDonald, M.A.

    1993-01-01

    The authors describe a spectrometer system developed for electron, ion, and x-ray spectroscopy of gas-phase atoms and molecules following inner-shell excitation by tunable synchrotron radiation. The spectrometer has been used on beamline X-24A at the National Synchrotron Light Source for excitation-dependent studies of Ar L-shell and K-shell photoexcitation and vacancy decay processes. The instrumentation and experimental methods are discussed, and examples are given of electron spectra and coincidence spectra between electrons and fluorescent x-rays

  20. Ion production and trapping in electron rings

    International Nuclear Information System (INIS)

    Gluckstern, R.C.; Ruggiero, A.G.

    1979-08-01

    The electron beam in the VUV and X-ray rings of NSLS will ionize residual gas by collisions. Positive ions will be produced with low velocity, and will be attracted by the electron beam to the beam axis. If they are trapped in stable (transverse) orbits, they may accumulate, thereby increasing the ν/sub x,z/ of the individual electrons. Since the accumulated ions are unlikely to be of uniform density, a spread in ν/sub x,z/ will also occur. Should these effects be serious, it may be necessary to introduce clearing electrodes, although this may increase Z/n in the rings, thereby adding to longitudinal instability problems. The seriousness of the above effect for the VUV and X-ray rings is estimated

  1. Electron-ion recombination in merged beams

    International Nuclear Information System (INIS)

    Wolf, A.; Habs, D.; Lampert, A.; Neumann, R.; Schramm, U.; Schuessler, T.; Schwalm, D.

    1993-01-01

    Detailed studies of recombination processes between electrons and highly charged ions have become possible by recent improvements of merged-beams experiments. We discuss in particular measurements with stored cooled ion beams at the Test Storage Ring (TSR) in Heidelberg. The cross section of dielectronic recombination was measured with high energy resolution for few-electron systems up to the nuclear charge of Cu at a relative energy up to 2.6 keV. At low energy (∼0.1 eV) total recombination rates of several ions were measured and compared with calculated radiative recombination rates. Laser-stimulated recombination of protons and of C 6+ ions was investigated as a function of the photon energy using visible radiation. Both the total recombination rates and the stimulated recombination spectra indicate that in spite of the short interaction time in merged beams, also collisional capture of electrons into weakly bound levels (related to three-body recombination) could be important

  2. Electron - ion recombination processes - an overview

    International Nuclear Information System (INIS)

    Hahn, Yukap

    1997-01-01

    Extensive theoretical and experimental studies have been carried out for the past 20 years on electron - ion recombination processes, as they are applied to the analysis of astrophysical and laboratory plasmas. We review the basic understanding gained through these efforts, with emphasis on some of the more recent progress made in recombination theory as the recombining system is affected by time-dependent electric fields and plasma particles at low temperature. Together with collisional ionization and excitation processes, recombination is important in determining ionization balance and excited-state population in non-equilibrium plasmas. The radiation emitted by plasmas is usually the principal medium with which to study the plasma condition, as it is produced mainly during the recombination and decay of excited states of ions inside the plasma. This is especially true when the plasma under study is not readily accessible by direct probes, as in astrophysical plasmas. Moreover, external probes may sometimes cause undesirable disturbances of the plasma. Electron-ion recombination proceeds in several different modes. The direct modes include three-body recombination (TBR) and one-step radiative recombination (RR), all to the ground- and singly-excited states of the target ions. By contrast, the indirect resonant mode is a two-step dielectronic recombination (DR), which proceeds first with the formation of doubly-excited states by radiationless excitation/capture. The resonant states thus formed may relax by autoionization and/or radiative cascades. For more exotic modes of recombination, we consider off-shell dielectronic recombination (radiative DR = RDR), in which an electron capture is accompanied by simultaneous radiative emission and excitation of the target ion. Some discussion on attachment of electrons to neutral atoms, resulting in the formation of negative ions, is also given. When resonance states involve one or more electrons in high Rydberg states

  3. Electron paramagnetic resonance of transition ions

    CERN Document Server

    Abragam, Anatole

    1970-01-01

    This book is a reissue of a classic Oxford text, and provides a comprehensive treatment of electron paramagnetic resonance of ions of the transition groups. The emphasis is on basic principles, with numerous references to publications containing further experimental results and more detailed developments of the theory. An introductory survey gives a general understanding, and a general survey presents such topics as the classical and quantum resonance equations, thespin-Hamiltonian, Endor, spin-spin and spin-lattice interactions, together with an outline of the known behaviour of ions of each

  4. Measurement of few-electron uranium ions on a high-energy electron beam ion trap

    International Nuclear Information System (INIS)

    Beiersdorfer, P.

    1994-01-01

    The high-energy electron beam ion trap, dubbed Super-EBIT, was used to produce, trap, and excite uranium ions as highly charged as fully stripped U 92+ . The production of such highly charged ions was indicated by the x-ray emission observed with high-purity Ge detectors. Moreover, high-resolution Bragg crystal spectromters were used to analyze the x-ray emission, including a detailed measurement of both the 2s 1/2 -2p 3/2 electric dipole and 2p 1/2 -2p 3/2 magnetic dipole transitions. Unlike in ion accelerators, where the uranium ions move at relativistic speeds, the ions in this trap are stationary. Thus very precise measurements of the transition energies could be made, and the QED contribution to the transition energies could be measured within less than 1 %. Details of the production of these highly charged ions and their measurement is given

  5. Improvement of photoneutron spectrum measurement produced by bombardment of 2 GeV electrons above giant dipole resonance region

    International Nuclear Information System (INIS)

    Lee, H. S.; Park, J. S.; Choi, H. D.; Sato, Tatsuhiko; Shin, Kasuo; Ban, Syuichi

    2000-01-01

    Above the Giant Dipole Resonance (GDR) region, high energy photoneutron spectra produced by irradiation of 2.04 GeV electrons into Pb target were measured by Time-of-Flight (TOF) technique. The differential photoneutron yields were obtained at a fixed angle of 90 degrees to the electron beam direction. The TOF system consists of Pilot-U plastic scintillation detector, which has fast response time, and the high speed multiscaler or CAMAC TDC. In the improvement of experimental setup to extend the flight distance to 10.4 m lead to make the measurable energy to 500 MeV from 300 MeV. And using the TDC based electronics lead to use a veto counter. The results were compared with the calculated one by using EGS4 and Modified PICA95. The characteristics of this TOF system was introduced in this paper and the results for several measuring conditions, which are flight distance, TOF electronics, and type of neutron detector, were discussed to improve the accuracy of this measurement

  6. Electron-ion recombination at low energy

    International Nuclear Information System (INIS)

    Andersen, L.H.

    1993-01-01

    The work is based on results obtained with a merged-beams experiment. A beam of electronics with a well characterized density and energy distribution was merged with a fast, monoenergetic ion beam. Results have been obtained for radiative recombination and dielectronic recombination at low relative energies (0 to ∼70eV). The obtained energy resolution was improved by about a factor of 30. High vacuum technology was used to suppress interactions with electrons from the environments. The velocity distribution of the electron beam was determined. State-selective dielectronic-recombination measurements were performable. Recombination processes were studied. The theoretical background for radiative recombination and Kramers' theory are reviewed. The quantum mechanical result and its relation to the semiclassical theory is discussed. Radiative recombination was also measured with several different non-bare ions, and the applicability of the semiclassical theory to non-bare ions was investigated. The use of an effective charge is discussed. For dielectronic recombination, the standard theoretical approach in the isolated resonance and independent-processes approximation is debated. The applicability of this method was tested. The theory was able to reproduce most of the experimental data except when the recombination process was sensitive to couplings between different electronic configurations. The influence of external perturbing electrostatic fields is discussed. (AB) (31 refs.)

  7. Design study of primary ion provider for relativistic heavy ion collider electron beam ion source.

    Science.gov (United States)

    Kondo, K; Kanesue, T; Tamura, J; Okamura, M

    2010-02-01

    Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented.

  8. Spatial distribution of bremsstrahlung in water and water-iron by 22-MeV electron bombardment measured with activation detectors

    International Nuclear Information System (INIS)

    Nakamura, Takashi; Nishimoto, Takanao; Hirayama, Hideo.

    1977-01-01

    The spatial distributions of bremsstrahlung in water (1 m thick) and water (60 cm thick)-iron (6.3 cm thick) bombarded by 22-MeV electrons were measured by using a new activation method which we developed. These informations are useful for studying shielding, residual activity and radiation damage of accelerator and target materials. From the measured activities, the bremsstrahlung spectra in water were evaluated with the LYRA and the SAND-II unfolding codes. The evaluated spectra were in good agreement with the analytical calculation by the DIBRE code, except for the higher energy ends. The longitudinal and the lateral distributions of bremsstrahlung flux in water were obtained by integrating the evaluated spectra above 8 MeV. The agreement of the experimental and the calculated flux distributions was very good except for a large angle to beam direction. The total photon number crossing a plane normal to the beam axis attenuates exponentially along the axial depth. The iso-flux contour of bremsstrahlung flux was given by interpolating the flux distribution curves. Only the saturated activities of gold detectors were obtained for water-iron in good experimental accuracy. The spatial distribution of gold saturated activities in water-iron clearly shows the attenuating effect due to strong absorption in iron. (auth.)

  9. The erosion and erosion products of tungsten and carbon based materials bombarded by high energy pulse electron beam

    International Nuclear Information System (INIS)

    Liu Xiang; Zhang Fu; Xu Zengyu; Liu Yong; Yoshida, N.; Noda, N.

    2002-01-01

    In this paper, the erosion behaviors and erosion products of tungsten and some carbon based materials, such as graphite, C/C composite and B 4 C/Cu functionally graded material, were investigated by using a pulse electron beam to simulate the vertical displacement events (VDE) process. The authors will focus on the forms and differences of erosion products among these testing materials, and make clear to their erosion mechanisms

  10. Nonextensive electron and ion dust charging currents

    International Nuclear Information System (INIS)

    Amour, Rabia; Tribeche, Mouloud

    2011-01-01

    The correct nonextensive electron and ion charging currents are presented for the first time based on the orbit motion limited approach. For -1< q<1, where q measures the amount of plasma nonextensivity, the nonextensive electron charging current is expressed in terms of the hypergeometric function. The variable dust charge is expressed in terms of the Lambert function and we take advantage of this transcendental function to investigate succinctly the effects of nonextensive charge carriers. The obtained formulas bring a possibility to build theories on nonlinear collective process in variable charge nonextensive dusty plasmas.

  11. Pilot scale electron bombardment furnace for continuous casting; application to the trial preparation of 20 kg of uranium monocarbide rods

    International Nuclear Information System (INIS)

    Trouve, J.; Genard, R.; Treillou, A.; Accary, A.

    1964-01-01

    The authors describe a pilot scale electron beam furnace designed for continuous melting and casting of uranium-carbon alloys. This equipment allows the melting and casting processes to be completely automatically controlled, the cooling being carried out under vacuum and the discharge being effected without breaking the vacuum. In a pre-production run of 20 kg of slugs, the composition of practically all the pieces was controlled within ± 0,1 per cent C. The output of the furnace was 2,2 kg/hour. (authors) [fr

  12. Electron bombardment cross-linking of coating materials. Pt.2. Analysis of patent literature on formulating radiation-hardenable binders

    International Nuclear Information System (INIS)

    Mileo, J.-C.

    1976-01-01

    The process of drying paints and varnishes by electron irradiation is analyzed from the chemical standpoint. A review is made of the different methods of producing radiation hardenable resins that have resulted in abundant patent literature. These resins are classified according to the nature of the reactive unsaturations they contain: unsaturations of the maleic ester type; simple (meth)acrylic esters and amides; β-hydroxyl (meth)acrylic esters, their (un)saturated esters and other derivatives; siloxanes; maleimides; allylic unsaturations; saturated resins [fr

  13. Specimen preparation by ion beam slope cutting for characterization of ductile damage by scanning electron microscopy.

    Science.gov (United States)

    Besserer, Hans-Bernward; Gerstein, Gregory; Maier, Hans Jürgen; Nürnberger, Florian

    2016-04-01

    To investigate ductile damage in parts made by cold sheet-bulk metal forming a suited specimen preparation is required to observe the microstructure and defects such as voids by electron microscopy. By means of ion beam slope cutting both a targeted material removal can be applied and mechanical or thermal influences during preparation avoided. In combination with scanning electron microscopy this method allows to examine voids in the submicron range and thus to analyze early stages of ductile damage. In addition, a relief structure is formed by the selectivity of the ion bombardment, which depends on grain orientation and microstructural defects. The formation of these relief structures is studied using scanning electron microscopy and electron backscatter diffraction and the use of this side effect to interpret the microstructural mechanisms of voids formation by plastic deformation is discussed. A comprehensive investigation of the suitability of ion beam milling to analyze ductile damage is given at the examples of a ferritic deep drawing steel and a dual phase steel. © 2016 Wiley Periodicals, Inc.

  14. Effect of the energy of bombarding electrons on the conductivity of n-4H-SiC (CVD) epitaxial layers

    Energy Technology Data Exchange (ETDEWEB)

    Kozlovski, V. V., E-mail: kozlovski@physics.spbstu.ru [Peter the Great St. Petersburg State Polytechnic University (Russian Federation); Lebedev, A. A.; Strel’chuk, A. M.; Davidovskaya, K. S. [Ioffe Physical–Technical Institute (Russian Federation); Vasil’ev, A. E. [Peter the Great St. Petersburg State Polytechnic University (Russian Federation); Makarenko, L. F. [Belarusian State University (Belarus)

    2017-03-15

    The electrical characteristics of epitaxial layers of n-4H-SiC (CVD) irradiated with 0.9 and 3.5MeV electrons are studied. It is shown that the donor removal rate becomes nearly four times higher as the energy of impinging electrons increases by a factor of 4, although the formation cross section of primary radiation defects (Frenkel pairs in the carbon sublattice) responsible for conductivity compensation of the material is almost energy independent in this range. It is assumed that the reason for the observed differences is the influence exerted by primary knocked-out atoms. First, cascade processes start to manifest themselves with increasing energy of primary knocked-out atoms. Second, the average distance between genetically related Frenkel pairs grows, and, as a consequence, the fraction of defects that do not recombine under irradiation becomes larger. The recombination radius of Frenkel pairs in the carbon sublattice is estimated and the possible charge state of the recombining components is assessed.

  15. Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

    Directory of Open Access Journals (Sweden)

    Hery Suyanto

    2016-08-01

    Full Text Available A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns and picosecond (ps lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS using He ambient gas.

  16. Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

    Energy Technology Data Exchange (ETDEWEB)

    Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, Rawamangun, Jakarta 12440 (Indonesia); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Lie, Tjung Jie; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha,Bandung 40132 (Indonesia); Kagawa, Kiichiro [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Fukui Science Education Academy, Takagi Chuo 2 chome, Fukui 910-0804 (Japan)

    2016-08-15

    A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns) and picosecond (ps) lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE) mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS) using He ambient gas.

  17. Multiple Electron Stripping of Heavy Ion Beams

    International Nuclear Information System (INIS)

    Mueller, D.; Grisham, L.; Kaganovich, I.; Watson, R. L.; Horvat, V.; Zaharakis, K. E.; Peng, Y.

    2002-01-01

    One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 Mev/amu with charge state 1 currently do not exist. Hence, the stripping cross-sections used to model the performance of heavy ion fusion driver beams have, up to now, been based upon theoretical calculations. We have investigated experimentally the stripping of 3.4 Mev/amu Kr 7+ and Xe +11 in N2; 10.2 MeV/amu Ar +6 in He, N2, Ar and Xe; 19 MeV/amu Ar +8 in He, N2, Ar and Xe; 30 MeV He 1 + in He, N2, Ar and Xe; and 38 MeV/amu N +6 in He, N2, Ar and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters

  18. Electron transport effects in ion induced electron emission

    Energy Technology Data Exchange (ETDEWEB)

    Dubus, A. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. FD Roosevelt, B-1050 Brussels (Belgium)]. E-mail: adubus@ulb.ac.be; Pauly, N. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. FD Roosevelt, B-1050 Brussels (Belgium); Roesler, M. [Karl-Pokern-Str. 12, D-12587 Berlin (Germany)

    2007-03-15

    Ion induced electron emission (IIEE) is usually described as a three-step process, i.e. electron excitation by the incident projectile, electron transport (and multiplication) and electron escape through the potential barrier at the surface. In many cases, the first step of the process has been carefully described. The second step of the process, i.e. electron transport and multiplication, has often been treated in a very rough way, a simple decreasing exponential law being sometimes used. It is precisely the aim of the present work to show the importance of a correct description of electron transport and multiplication in a theoretical calculation of IIEE. A short overview of the electron transport models developed for IIEE is given in this work. The so-called 'Infinite medium slowing-down model' often used in recent works is evaluated by means of Monte Carlo simulations. In particular, the importance of considering correctly the semi-infinite character of the medium and the boundary condition at the vacuum-medium interface is discussed. Quantities like the electron escape depth are also briefly discussed. This evaluation has been performed in the particular case of protons (25keV

  19. Influence of helium-ion bombardment on the optical properties of ZnO nanorods/p-GaN light-emitting diodes

    Science.gov (United States)

    Alvi, Naveed Ul Hassan; Hussain, Sajjad; Jensen, Jen; Nur, Omer; Willander, Magnus

    2011-12-01

    Light-emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods grown by vapor-liquid-solid catalytic growth method were irradiated with 2-MeV helium (He+) ions. The fabricated LEDs were irradiated with fluencies of approximately 2 × 1013 ions/cm2 and approximately 4 × 1013 ions/cm2. Scanning electron microscopy images showed that the morphology of the irradiated samples is not changed. The as-grown and He+-irradiated LEDs showed rectifying behavior with the same I-V characteristics. Photoluminescence (PL) measurements showed that there is a blue shift of approximately 0.0347 and 0.082 eV in the near-band emission (free exciton) and green emission of the irradiated ZnO nanorods, respectively. It was also observed that the PL intensity of the near-band emission was decreased after irradiation of the samples. The electroluminescence (EL) measurements of the fabricated LEDs showed that there is a blue shift of 0.125 eV in the broad green emission after irradiation and the EL intensity of violet emission approximately centered at 398 nm nearly disappeared after irradiations. The color-rendering properties show a small decrease in the color-rendering indices of 3% after 2 MeV He+ ions irradiation.

  20. Evaluation of computational models and cross sections used by MCNP6 for simulation of characteristic X-ray emission from thick targets bombarded by kiloelectronvolt electrons

    Energy Technology Data Exchange (ETDEWEB)

    Poškus, A., E-mail: andrius.poskus@ff.vu.lt

    2016-09-15

    This paper evaluates the accuracy of the single-event (SE) and condensed-history (CH) models of electron transport in MCNP6.1 when simulating characteristic K{sub α}, total K (=K{sub α} + K{sub β}) and L{sub α} X-ray emission from thick targets bombarded by electrons with energies from 5 keV to 30 keV. It is shown that the MCNP6.1 implementation of the CH model for the K-shell impact ionization leads to underestimation of the K yield by 40% or more for the elements with atomic numbers Z < 15 and overestimation of the K{sub α} yield by more than 40% for the elements with Z > 25. The L{sub α} yields are underestimated by more than an order of magnitude in CH mode, because MCNP6.1 neglects X-ray emission caused by electron-impact ionization of L, M and higher shells in CH mode (the L{sub α} yields calculated in CH mode reflect only X-ray fluorescence, which is mainly caused by photoelectric absorption of bremsstrahlung photons). The X-ray yields calculated by MCNP6.1 in SE mode (using ENDF/B-VII.1 library data) are more accurate: the differences of the calculated and experimental K yields are within the experimental uncertainties for the elements C, Al and Si, and the calculated K{sub α} yields are typically underestimated by (20–30)% for the elements with Z > 25, whereas the L{sub α} yields are underestimated by (60–70)% for the elements with Z > 49. It is also shown that agreement of the experimental X-ray yields with those calculated in SE mode is additionally improved by replacing the ENDF/B inner-shell electron-impact ionization cross sections with the set of cross sections obtained from the distorted-wave Born approximation (DWBA), which are also used in the PENELOPE code system. The latter replacement causes a decrease of the average relative difference of the experimental X-ray yields and the simulation results obtained in SE mode to approximately 10%, which is similar to accuracy achieved with PENELOPE. This confirms that the DWBA inner

  1. Heavy-ion induced secondary electron emission from Mg, Al, and Si partially covered with oxygen

    International Nuclear Information System (INIS)

    Weng, J; Veje, E.

    1984-01-01

    We have bombarded Mg, Al, and Si with 80 keV Ar + ions and measured the secondary electron emission yields at projectile incidence angles from 0 0 to 85 0 , with oxygen present at the target as well as under UHV conditions. The total secondary electron emission yields are found to depend fairly much on the amount of oxygen present. The three elements studied show relatively large individual variations. For all three elements, and with as well as without oxygen present, the relative secondary electron emission yield is observed to vary as 1/cos v, where v is the angle of incidence of the projectiles. This seems to indicate that the secondary electron production is initiated uniformly along the projectile path in the solid, in a region close to the surface. The results are discussed, and it is tentatively suggested, that the increase in secondary electron emission, caused by the presence of oxygen, originates from neutralization of sputtered oxygen, which initially is sitting as O 2- ions. (orig.)

  2. Swift-heavy ion track electronics (SITE)

    International Nuclear Information System (INIS)

    Fink, D.; Chadderton, L.T.; Hoppe, K.; Fahrner, W.R.; Chandra, A.; Kiv, A.

    2007-01-01

    An overview about the state-of-art of the development of a new type of nanoelectronics based on swift-heavy ions is given. Polymeric as well as silicon-based substrates have been used, and both latent and etched ion tracks play a role. Nowadays the interest has shifted from simple scaling-down of capacitors, magnets, transformers, diodes, transistors, etc. towards new types of ion track-based structures hitherto unknown in electronics. These novel structures, denoted by the acronyms 'TEAMS' (tunable electrically anisotropic material on semiconductor) and 'TEMPOS' (tunable electronic material with pores in oxide on semiconductor), may exhibit properties of tunable resistors, capacitors, diodes, sensors and transistors. Their general current/voltage characteristics are outlined. As these structures are often influenced by ambient physical or chemical parameters they also act as sensors. A peculiarity of these structures is the occurrence of negative differential resistances (NDRs) which makes them feasible for applications in tunable flip-flops, amplifiers and oscillators

  3. Swift-heavy ion track electronics (SITE)

    Energy Technology Data Exchange (ETDEWEB)

    Fink, D. [Hahn-Meitner-Institute Berlin, Glienicker Str. 100, D-14109 Berlin (Germany)]. E-mail: fink@hmi.de; Chadderton, L.T. [Institute of Advanced Studies, ANU Canberra, G.P.O. Box 4, ACT (Australia); Hoppe, K. [South Westfalia University of Applied Sciences, Hagen (Germany); Fahrner, W.R. [Chair of Electronic Devices, Inst. of Electrotechnique, Fernuniversitaet, Hagen (Germany); Chandra, A. [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Kiv, A. [Ben Gurion University of the Negev, Israel, P.O. Box 653, Beer-Sheva, 84105 (Israel)

    2007-08-15

    An overview about the state-of-art of the development of a new type of nanoelectronics based on swift-heavy ions is given. Polymeric as well as silicon-based substrates have been used, and both latent and etched ion tracks play a role. Nowadays the interest has shifted from simple scaling-down of capacitors, magnets, transformers, diodes, transistors, etc. towards new types of ion track-based structures hitherto unknown in electronics. These novel structures, denoted by the acronyms 'TEAMS' (tunable electrically anisotropic material on semiconductor) and 'TEMPOS' (tunable electronic material with pores in oxide on semiconductor), may exhibit properties of tunable resistors, capacitors, diodes, sensors and transistors. Their general current/voltage characteristics are outlined. As these structures are often influenced by ambient physical or chemical parameters they also act as sensors. A peculiarity of these structures is the occurrence of negative differential resistances (NDRs) which makes them feasible for applications in tunable flip-flops, amplifiers and oscillators.

  4. Heavy Ion Injection Into Synchrotrons, Based On Electron String Ion Sources

    CERN Document Server

    Donets, E E; Syresin, E M

    2004-01-01

    A possibility of heavy ions injection into synchrotrons is discussed on the base of two novel ion sources, which are under development JINR during last decade: 1) the electron string ion source (ESIS), which is a modified version of a conventional electron beam ion source (EBIS), working in a reflex mode of operation, and 2) the tubular electron string ion source (TESIS). The Electron String Ion Source "Krion-2" (VBLHE, JINR, Dubna) with an applied confining magnetic field of 3 T was used for injection into the superconducting JINR synchrotron - Nuclotron and during this runs the source provided a high pulse intensity of the highly charged ion beams: Ar16+

  5. Magnetized relativistic electron-ion plasma expansion

    Science.gov (United States)

    Benkhelifa, El-Amine; Djebli, Mourad

    2016-03-01

    The dynamics of relativistic laser-produced plasma expansion across a transverse magnetic field is investigated. Based on a one dimensional two-fluid model that includes pressure, enthalpy, and rest mass energy, the expansion is studied in the limit of λD (Debye length) ≤RL (Larmor radius) for magnetized electrons and ions. Numerical investigation conducted for a quasi-neutral plasma showed that the σ parameter describing the initial plasma magnetization, and the plasma β parameter, which is the ratio of kinetic to magnetic pressure are the key parameters governing the expansion dynamics. For σ ≪ 1, ion's front shows oscillations associated to the break-down of quasi-neutrality. This is due to the strong constraining effect and confinement of the magnetic field, which acts as a retarding medium slowing the plasma expansion.

  6. A high-resolution detector based on liquid-core scintillating fibres with readout via an electron-bombarded charge-coupled device

    International Nuclear Information System (INIS)

    Cianfarani, C.; Duane, A.; Fabre, J.P.; Frenkel, A.; Golovkin, S.V.; Gorin, A.M.; Harrison, K.; Kozarenko, E.N.; Kushnirenko, A.E.; Ladygin, E.A.; Martellotti, G.; Medvedkov, A.M.; Nass, P.A.; Obudovski, V.P.; Penso, G.; Petukhov, Yu.P.; Siegmund, W.P.; Tyukov, V.E.; Vasilchenko, V.G.

    1994-01-01

    This paper is a presentation of results from tests in a 5 GeV/c hadron beam of detectors based on liquid-core scintillating fibres, each fibre consisting of a glass capillary filled with organic liquid scintillator. Fibre readout was performed via an Electron-Bombarded Charge-Coupled Device (EBCCD) image tube, a novel instrument that combines the functions of a high-gain, gated image intensifier and a Charge-Coupled Device. Using 1-methylnaphthalene doped with 3 g/l of R45 as liquid scintillator, the attenuation lengths obtained for light propagation over distances greater than 16 cm were 1.5 m in fibres of 20 μm core and 1.0 m in fibres of 16 μm core. For particles that crossed the fibres of 20 μm core at distances of ∼1.8 cm and ∼95 cm from the fibres' readout ends, the recorded hit densities were 5.3 mm -1 and 2.5 mm -1 respectively. Using 1-methylnaphthalene doped with 3.6 g/l of R39 as liquid scintillator and fibres of 75 μm core, the hit density obtained for particles that crossed the fibres at a distance of ∼1.8 cm from their readout ends was 8.5 mm -1 . With a specially designed bundle of tapered fibres, having core diameters that smoothly increase from 16 μm to 75 μm, a spatial precision of 6 μm was measured. (orig.)

  7. Modeling ion sensing in molecular electronics

    International Nuclear Information System (INIS)

    Chen, Caroline J.; Smeu, Manuel; Ratner, Mark A.

    2014-01-01

    We examine the ability of molecules to sense ions by measuring the change in molecular conductance in the presence of such charged species. The detection of protons (H + ), alkali metal cations (M + ), calcium ions (Ca 2+ ), and hydronium ions (H 3 O + ) is considered. Density functional theory (DFT) is used within the Keldysh non-equilibrium Green's function framework (NEGF) to model electron transport properties of quinolinedithiol (QDT, C 9 H 7 NS 2 ), bridging Al electrodes. The geometry of the transport region is relaxed with DFT. The transport properties of the device are modeled with NEGF-DFT to determine if this device can distinguish among the M + + QDT species containing monovalent cations, where M + = H + , Li + , Na + , or K + . Because of the asymmetry of QDT in between the two electrodes, both positive and negative biases are considered. The electron transmission function and conductance properties are simulated for electrode biases in the range from −0.5 V to 0.5 V at increments of 0.1 V. Scattering state analysis is used to determine the molecular orbitals that are the main contributors to the peaks in the transmission function near the Fermi level of the electrodes, and current-voltage relationships are obtained. The results show that QDT can be used as a proton detector by measuring transport through it and can conceivably act as a pH sensor in solutions. In addition, QDT may be able to distinguish among different monovalent species. This work suggests an approach to design modern molecular electronic conductance sensors with high sensitivity and specificity using well-established quantum chemistry

  8. Newly appreciated roles for electrons in ion-atom collisions

    International Nuclear Information System (INIS)

    Sellin, I.A.

    1990-01-01

    Since the previous Debrecen workshop on High-Energy Ion-Atom Collisions there have been numerous experiments and substantial theoretical developments in the fields of fast ion-atom and ion- solid collisions concerned with explicating the previously largely underappreciated role of electrons as ionizing and exciting agents in such collisions. Examples to be discussed include the double electron ionization problem in He; transfer ionization by protons in He; double excitation in He; backward scattering of electrons in He; the role of electron-electron interaction in determining beta parameters for ELC; projectile K ionization by target electrons; electron spin exchange in transfer excitation; electron impact ionization in crystal channels; resonant coherent excitation in crystal channels; excitation and dielectronic recombination in crystal channels; resonant transfer and excitation; the similarity of recoil ion spectra observed in coincidence with electron capture vs. electron loss; and new research on ion-atom collisions at relativistic energies

  9. GPDs at an electron ion collider

    International Nuclear Information System (INIS)

    Fazio, Salvatore

    2013-01-01

    The feasibility for a precise determination of Generalized Parton Distribution (GPDs) functions at an Electron Ion Collider (EIC) has been explored. The high luminosity of the machine, together with the large resolution and rapidity acceptance of the new dedicated detector, will open opportunity for high precision measurements of GPDs. We report on the study of GPDs from deeply virtual Compton scattering (DVCS). We also point out that such measurements at a proposed EIC provide insight to both, the transverse distribution of sea quarks and gluons as well as the proton spin decomposition.

  10. GPDs at an electron ion collider

    Energy Technology Data Exchange (ETDEWEB)

    Fazio, Salvatore [Brookhaven National Laboratory, 11973 Upton NY (United States)

    2013-04-15

    The feasibility for a precise determination of Generalized Parton Distribution (GPDs) functions at an Electron Ion Collider (EIC) has been explored. The high luminosity of the machine, together with the large resolution and rapidity acceptance of the new dedicated detector, will open opportunity for high precision measurements of GPDs. We report on the study of GPDs from deeply virtual Compton scattering (DVCS). We also point out that such measurements at a proposed EIC provide insight to both, the transverse distribution of sea quarks and gluons as well as the proton spin decomposition.

  11. High current density ion source

    International Nuclear Information System (INIS)

    King, H.J.

    1977-01-01

    A high-current-density ion source with high total current is achieved by individually directing the beamlets from an electron bombardment ion source through screen and accelerator electrodes. The openings in these screen and accelerator electrodes are oriented and positioned to direct the individual beamlets substantially toward a focus point. 3 figures, 1 table

  12. Progress in electron- and ion-interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Hasselbach, Franz [Institut fuer Angewandte Physik der Universitaet Tuebingen, Auf der Morgenstelle 10, D-72076 Tuebingen (Germany)], E-mail: franz.hasselbach@uni-tuebingen.de

    2010-01-15

    In the 1970s the prominent goal was to overcome the limitations of electron microscopy caused by aberrations of electron lenses by the development of electron holography. In the meantime this problem has been solved, not only in the roundabout way of holography, but directly by correcting the aberrations of the lenses. Nevertheless, many quantitative electron microscopical measurement methods-e.g. mapping and visualization of electric and magnetic fields-were developed within the context of holography and have become fields of their own. In this review we focus on less popular electron interferometric experiments which complement the field of electron holography. The paper is organized as follows. After a short sketch of the development of electron biprism interferometry after its invention in 1954, recent advances in technology are discussed that made electron biprism interferometry an indispensable tool for solving fundamental and applied questions in physics: the development and preparation of conventional and single-atom field electron and field ion sources with their extraordinary properties. Single- and few-atom sources exhibit spectacular features: their brightness at 100 keV exceeds that of conventional field emitters by two orders in magnitude. Due to the extremely small aberrations of diode field emitter extraction optics, the virtual source size of single-atom tips is on the order of 0.2 nm. As a consequence it illuminates an area 7 cm in diameter on a screen at a distance of 15 cm coherently. Projection electron micrographs taken with these sources reach spatial resolutions of atomic dimensions and in-line holograms are-due to the absence of lenses with their aberrations-not blurred. Their reconstruction is straightforward. By addition of a carbon nanotube biprism into the beam path of a projection microscope a lensless electron interferometer has been realized. In extremely ultrahigh vacuum systems flicker noise is practically absent in the new sources

  13. Progress in electron- and ion-interferometry

    International Nuclear Information System (INIS)

    Hasselbach, Franz

    2010-01-01

    In the 1970s the prominent goal was to overcome the limitations of electron microscopy caused by aberrations of electron lenses by the development of electron holography. In the meantime this problem has been solved, not only in the roundabout way of holography, but directly by correcting the aberrations of the lenses. Nevertheless, many quantitative electron microscopical measurement methods-e.g. mapping and visualization of electric and magnetic fields-were developed within the context of holography and have become fields of their own. In this review we focus on less popular electron interferometric experiments which complement the field of electron holography. The paper is organized as follows. After a short sketch of the development of electron biprism interferometry after its invention in 1954, recent advances in technology are discussed that made electron biprism interferometry an indispensable tool for solving fundamental and applied questions in physics: the development and preparation of conventional and single-atom field electron and field ion sources with their extraordinary properties. Single- and few-atom sources exhibit spectacular features: their brightness at 100 keV exceeds that of conventional field emitters by two orders in magnitude. Due to the extremely small aberrations of diode field emitter extraction optics, the virtual source size of single-atom tips is on the order of 0.2 nm. As a consequence it illuminates an area 7 cm in diameter on a screen at a distance of 15 cm coherently. Projection electron micrographs taken with these sources reach spatial resolutions of atomic dimensions and in-line holograms are-due to the absence of lenses with their aberrations-not blurred. Their reconstruction is straightforward. By addition of a carbon nanotube biprism into the beam path of a projection microscope a lensless electron interferometer has been realized. In extremely ultrahigh vacuum systems flicker noise is practically absent in the new sources

  14. An improved electron impact ion source power supply

    International Nuclear Information System (INIS)

    Beaver, E.M.

    1974-01-01

    An electron impact ion source power supply has been developed that offers improved ion beam stability. The electrical adjustments of ion source parameters are more flexible, and safety features are incorporated to protect the electron emitting filament from accidental destruction. (author)

  15. Dielectronic recombination measurements using the Electron Beam Ion Trap

    International Nuclear Information System (INIS)

    Knapp, D.A.

    1991-01-01

    We have used the Electron Beam Ion Trap at LLNL to study dielectronic recombination in highly charged ions. Our technique is unique because we observe the x-rays from dielectronic recombination at the same time we see x-rays from all other electron-ion interactions. We have recently taken high-resolution, state-selective data that resolves individual resonances

  16. Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range

    International Nuclear Information System (INIS)

    Vidovic, Z.

    1997-06-01

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H 0 , H 2 + and H 3 + projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H 2 + and H 3 + polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

  17. Electron Acoustic Waves in Pure Ion Plasmas

    Science.gov (United States)

    Anderegg, F.; Driscoll, C. F.; Dubin, D. H. E.; O'Neil, T. M.

    2009-11-01

    Electron Acoustic Waves (EAW) are the low frequency branch of electrostatic plasma waves. These waves exist in neutralized plasmas, pure electron plasmas and in pure ion plasmasfootnotetextF. Anderegg et al., PRL 102, 095001 (2009) and PoP 16, 055705 (2009). (where the name is deceptive). Here, we observe standing mθ= 0 mz= 1 EAWs in a pure ion plasma column. At small amplitude, the EAWs have a phase velocity vph ˜1.4 v, and the frequencies are in close agreement with theory. At moderate amplitudes, waves can be excited over a broad range of frequencies, with observed phase velocities in the range of 1.4 v vph diagnostic shows that particles slower than vph oscillate in phase with the wave, while particles moving faster than vph oscillate 180^o out of phase with the wave. From a fluid perspective, this gives an unusual negative dynamical compressibility. That is, the wave pressure oscillations are 180^o out of phase from the density oscillations, almost fully canceling the electrostatic restoring force, giving the low and malleable frequency.

  18. Electron microscopy studies of ion implanted silicon

    International Nuclear Information System (INIS)

    Seshan, K.

    1975-11-01

    The nature of defects resulting from the implantation of phosphorous ions into doped silicon and a model of how they form are reported. This involved an electron microscope study of the crystallographic defects (in the 300A size range in concentration of 10 15 /cm 3 ) that form upon annealing. Images formed by these crystallographic defects are complex and that nonconventional imaging techniques are required for their characterization. The images of these small defects (about 300A) are sensitive to various parameters, such as foil thickness, their position in the foil, and diffracting conditions. The defects were found to be mostly interstitial hexagonal Frank loops lying on the four [111] planes and a few perfect interstitial loops; these loops occurred in concentrations of about 10 16 /cm 3 . In addition, ''rod like'' linear defects that are shown to be interstitial are also found in concentrations of 10 13 /cm 3 . It was found that the linear defects require boron for their formation. A model is proposed to account for the interstitial defects. The number of point defects that make up the defects is of the same order as the number of implanted ions. The model predicts that only interstitial loops ought to be observed in agreement with several recent investigations. Dislocation models of the loops are examined and it is shown that phosphorous ions could segregate to the Frank loops, changing their displacement vectors to a/x[111]. (x greater than 3) thus explaining the contrast effects observed. It would also explain the relative electrical inactivity of P + ion implants

  19. Pilot scale electron bombardment furnace for continuous casting; application to the trial preparation of 20 kg of uranium monocarbide rods; Appareil pilote de fusion par bombardement d'electrons et coulee continue - application a un essai de fabrication portant sur 20 kg de barreaux de monocarbure d'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Trouve, J; Genard, R; Treillou, A; Accary, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The authors describe a pilot scale electron beam furnace designed for continuous melting and casting of uranium-carbon alloys. This equipment allows the melting and casting processes to be completely automatically controlled, the cooling being carried out under vacuum and the discharge being effected without breaking the vacuum. In a pre-production run of 20 kg of slugs, the composition of practically all the pieces was controlled within {+-} 0,1 per cent C. The output of the furnace was 2,2 kg/hour. (authors) [French] Les auteurs decrivent un appareil pilote de fusion par bombardement d'electrons et coulee continue. Cet appareil, muni d'un systeme de coulee automatique, permet la fusion et la coulee d'alliages uranium-carbone, leur refroidissement sous vide et leur defournement, toutes ces operations se deroulant d'une maniere continue. Ils montrent qu'au cours d'une campagne preliminaire de fusion et coulee de 20 kg de barreaux, la teneur en carbone de la quasi-totalite des barreaux obtenus est controlee a 0,1 pour cent pres. La production horaire de l'appareillage est de 2,2 kg. (auteurs)

  20. Future directions in electron--ion collision physics

    International Nuclear Information System (INIS)

    Reed, K.J.; Griffin, D.C.

    1992-01-01

    This report discusses the following topics: Summary of session on synergistic co-ordination of theory and experiment; synergism between experiment and theory in atomic physics; comparison of theory and experiment for electron-ion excitation and ionization; summary of session on new theoretical and computational methods; new theoretical and computational methods-r-matrix calculations; the coulomb three-body problem: a progress report; summary of session on needs and applications for electron-ion collisional data; electron-ion collisions in the plasma edge; needs and applications of theoretical data for electron impact excitation; summary of session on relativistic effects, indirect effects, resonance, etc; direct and resonant processes in electron-ion collisions; relativistic calculations of electron impact ionization and dielectronic recombination cross section for highly charged ions; electron-ion recombination in the close-coupling approximation; modified resonance amplitudes with strongly correlated channels; a density-matrix approach to the broadening of spectral lines by autoionization, radiative transitions and electron-ion collisions; towards a time-dependent description of electron-atom/ion collisions two electron systems; and comments on inclusion of the generalized bright interaction in electron impact excitation of highly charged ions

  1. Electronic emission and electron guns

    International Nuclear Information System (INIS)

    Roy, Amitava

    2010-01-01

    This paper reviews the process of electron emission from metal surface. Although electrons move freely in conductors like metals, they normally do not leave the metal without some manipulation. In fact, heating and bombardment are the two primary ways in which electrons are emitted through the use of a heating element behind the cathode (termed thermionic emission) or as a result of bombardment with a beam of electrons, ions, or metastable atoms (termed secondary emission). Another important emission mechanism called Explosive Electron Emission (EEE) is also often used in various High Voltage Pulse Power Systems to generate very high current (few hundreds of kA) pulsed electron beams. The electron gun is the device in that it shoots off a continuous (or pulsed) stream of electrons. A brief idea about the evolution of the electron gun components and their basis of functioning are also discussed. (author)

  2. Bursts of electron waves modulated by oblique ion waves

    International Nuclear Information System (INIS)

    Boswell, R.W.

    1984-01-01

    Experimental evidence is presented which shows small packets of electron plasma waves modulated by large amplitude obliquely propagating non-linear ion plasma waves. Very often the whole system is modulated by an oscillation near the ion gyro frequency or its harmonics. The ion waves seem to be similar to those measured in the current carrying auroral plasma. These results suggest that the generation of ion and electron waves in the auroral plasma may be correlated

  3. Ion Acoustic Waves in the Presence of Electron Plasma Waves

    DEFF Research Database (Denmark)

    Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

    1977-01-01

    Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave.......Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave....

  4. Low energy electron-initiated ion-molecule reactions of ribose analogues

    International Nuclear Information System (INIS)

    Mozejko, P.

    2003-01-01

    Recent experiments in which plasmid DNA samples were bombarded with low energy ( 2 O, DNA bases, and sugar-phosphate backbone analogues. To this end, the cyclic molecule tetrahydrofuran, and its derivatives, provide useful models for the sugar-like molecules contained in the backbone of DNA. In addition to LEE induced dissociation by processes such as dissociative electron attachment (DEA), molecules may be damaged by ions and neutral species of non-thermal energies created by LEE in the surrounding environment. In this contribution, we investigate with electron stimulated desorption techniques, LEE damage to films of desoxy-ribose analogues in the presence of various molecular coadsorbates, that simulate changes in local molecular environment. In one type of experiments tetrahydrofuran is deposited onto multilayer O2. A desorbed signal of OH - indicates ion-molecule reactions of the type O - + C 4 H 8 O -> OH - + C 4 H 7 O, where the O - was formed initially by DEA to O 2 . Further electron stimulated desorption measurements for tetrahydrofuran and derivatives adsorbed on H 2 O, Kr, N 2 O and CH 3 OH will be presented and discussed

  5. Carbon contaminant in the ion processing of aluminum oxide film

    International Nuclear Information System (INIS)

    Chaug, Y.; Roy, N.

    1989-01-01

    Ion processing can induce contamination on the bombarded surface. However, this process is essential for the microelectronics device fabrication. Auger electron spectroscopy has been used to study the simultaneous deposition of carbon impurity during ion bombardment of magnetron rf-sputtering deposited aluminum oxide film. Ion bombardment on aluminum oxide results in a preferential removal of surface oxygen and a formation of a metastable state of aluminum suboxide. Cosputtered implanted carbon contaminant appears to have formed a new state of stoichiometry on the surface of the ion bombarded aluminum oxide and existed as an aluminum carbide. This phase has formed due to the interaction of the implanted carbon and the aluminum suboxide. The Ar + ion sputter etching rate is reduced for the carbon contaminated oxide. The electrical resistance of the aluminum oxide between two gold strips has been measured. It is found that the electrical resistance is also reduced due to the formation of the new stoichiometry on the surface

  6. Production processes of multiply charged ions by electron impact

    International Nuclear Information System (INIS)

    Oda, Nobuo

    1980-02-01

    First, are compared the foil or gas stripper and the ion sources utilizing electron-atom ionizing collisions, which are practically used or are under development to produce multiply charged ions. A review is made of the fundamental physical parameters such as successive ionization potentials and various ionization cross sections by electron impact, as well as the primary processes in multiply charged ion production. Multiply charged ion production processes are described for the different existing ion sources such as high temperature plasma type, ion-trapping type and discharge type. (author)

  7. Electron temperature effects for an ion beam source

    International Nuclear Information System (INIS)

    Uramoto, Joshin.

    1979-05-01

    A hydrogen high temperature plasma up to 200 eV is produced by acceleration of electrons in a hot hollow cathode discharge and is used as an ion beam source. Then, two characteristics are observed: A rate of the atomic ion (H + ) number increases above 70%. A perveance of the ion beam increases above 30 times compared with that of a cold plasma, while a floating potential of an ion acceleration electrode approaches an ion acceleration potential (- 500 V) according as an increment of the electron temperature. Moreover, a neutralized ion beam can be produced by only the negative floating electrode without an external power supply. (author)

  8. Coherent electromagnetic radiation of a combined electron-ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Pankratov, S G; Samoshenkov, Yu K [Vsesoyuznyj Nauchno-Issledovatel' skij Inst. Optiko-Fizicheskikh Izmerenij, Moscow (USSR)

    1977-07-01

    The intensity of coherent electromagnetic radiation due to interaction of a modulated electron beam with a modulated ion beam is calculated. It is shown that the radiation intensity has a sharp maximum at the frequency equal to the difference of the modulation frequency of the electron and ion beams. The results obtained are compared with those corresponding to the scattering of a modulated electron beam on randomly distributed gas ions.

  9. Electron energy recovery system for negative ion sources

    International Nuclear Information System (INIS)

    Dagenhart, W.K.; Stirling, W.L.

    1982-01-01

    An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90* to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy

  10. Electronic structures in ion-surface interactions

    International Nuclear Information System (INIS)

    Kiuchi, Masato; Takeuchi, Takae; Yamamoto, Masao.

    1997-01-01

    A chemical bond generated by the interaction between low energy ion and base was investigated by ab initio molecular orbital method. The effects of ion charge were studied by calculation of this method. When carbon ion approached to graphite base (C 24 H 12 ), the positive ion and the neutral atom covalently bonded, but the negative ion did not combine with it. When carbon ion was injected into h-BN base (B 12 N 12 H 12 , hexagonal system boron nitride), the positive ion and the neutron atom formed covalent bond and the van der Waals binding, and the negative ion interacted statically with it. (S.Y.)

  11. Ion age transport: developing devices beyond electronics

    Science.gov (United States)

    Demming, Anna

    2014-03-01

    There is more to current devices than conventional electronics. Increasingly research into the controlled movement of ions and molecules is enabling a range of new technologies. For example, as Weihua Guan, Sylvia Xin Li and Mark Reed at Yale University explain, 'It offers a unique opportunity to integrate wet ionics with dry electronics seamlessly'. In this issue they provide an overview of voltage-gated ion and molecule transport in engineered nanochannels. They cover the theory governing these systems and fabrication techniques, as well as applications, including biological and chemical analysis, and energy conversion [1]. Studying the movement of particles in nanochannels is not new. The transport of materials in rock pores led Klinkenberg to describe an analogy between diffusion and electrical conductivity in porous rocks back in 1951 [2]. And already in 1940, Harold Abramson and Manuel Gorin noted that 'When an electric current is applied across the living human skin, the skin may be considered to act like a system of pores through which transfer of substances like ragweed pollen extract may be achieved both by electrophoretic and by diffusion phenomena' [3]. Transport in living systems through pore structures on a much smaller scale has attracted a great deal of research in recent years as well. The selective transport of ions and small organic molecules across the cell membrane facilitates a number of functions including communication between cells, nerve conduction and signal transmission. Understanding these processes may benefit a wide range of potential applications such as selective separation, biochemical sensing, and controlled release and drug delivery processes. In Germany researchers have successfully demonstrated controlled ionic transport through nanopores functionalized with amine-terminated polymer brushes [4]. The polymer nanobrushes swell and shrink in response to changes in temperature, thus opening and closing the nanopore passage to ionic

  12. New experimental initiatives using very highly charged ions from an 'electron beam ion trap'

    International Nuclear Information System (INIS)

    Schneider, D.

    1996-01-01

    A short review of the experimental program in highly-charged heavy ion physics conducted at the Lawrence Livermore National Laboratory Electron Beam Ion Trap (EBIT) facility is presented. The heavy-ion research, involving ions up to fully stripped U 92+ , includes precision x-ray spectroscopy and lifetime studies, electron impact ionization and excitation cross section measurements. The investigations of ion-surface interactions following the impact of high-Z highly charged ions on surfaces are aimed to study the neutralization dynamics effecting the ion and the response of the surface as well. (author)

  13. Compton profiles by inelastic ion-electron scattering

    International Nuclear Information System (INIS)

    Boeckl, H.; Bell, F.

    1983-01-01

    It is shown that Compton profiles (CP) can be measured by inelastic ion-electron scattering. Within the impulse approximation the binary-encounter peak (BEP) reflects the CP of the target atom whereas the electron-loss peak (ELP) is given by projectile CP's. Evaluation of experimental data reveals that inelastic ion-electron scattering might be a promising method to supply inelastic electron or photon scattering for the determination of target CP's. The measurement of projectile CP's is unique to ion scattering since one gains knowledge about wave-function effects because of the high excitation degree of fast heavy-ion projectiles

  14. Electron emission from solids induced by swift heavy ions

    International Nuclear Information System (INIS)

    Xiao Guoqing

    2000-01-01

    The recent progresses in experimental and theoretical studies of the collision between swift heavy ion and solids as well as electron emission induced by swift heavy ion in solids were briefly reviewed. Three models, Coulomb explosion, thermal spike and repulsive long-lived states, for interpreting the atomic displacements stimulated by the electronic energy loss were discussed. The experimental setup and methods for measuring the electron emission from solids were described. The signification deviation from a proportionality between total electron emission yields and electronic stopping power was found. Auger-electron and convoy-electron spectra are thought to be a probe for investigating the microscopic production mechanisms of the electronic irradiation-damage. Electron temperature and track potential at the center of nuclear tracks in C and polypropylene foils induced by 5 MeV/u heavy ions, which are related to the electronic excitation density in metals and insulators respectively, were extracted by measuring the high resolution electron spectra

  15. Electron-ion correlation effects in ion-atom single ionization

    Energy Technology Data Exchange (ETDEWEB)

    Colavecchia, F.D.; Garibotti, C.R. [Centro Atomico Bariloche and Consejo Nacional de Investigaciones Cientificas y Tecnicas, 8400 San Carlos de Bariloche (Argentina); Gasaneo, G. [Departamento de Fisica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2000-06-28

    We study the effect of electron-ion correlation in single ionization processes of atoms by ion impact. We present a distorted wave model where the final state is represented by a correlated function solution of a non-separable three-body continuum Hamiltonian, that includes electron-ion correlation as coupling terms of the wave equation. A comparison of the electronic differential cross sections computed with this model with other theories and experimental data reveals that the influence of the electron-ion correlation is more significant for low energy emitted electrons. (author). Letter-to-the-editor.

  16. Ion implantation apparatus

    International Nuclear Information System (INIS)

    Forneris, J.L.; Hicks, W.W.; Keller, J.H.; McKenna, C.M.; Siermarco, J.A.; Mueller, W.F.

    1981-01-01

    The invention relates to ion bombardment or implantation apparatus. It comprises an apparatus for bombarding a target with a beam of ions, including an arrangement for measuring the ion beam current and controlling the surface potential of the target. This comprises a Faraday cage formed, at least in part, by the target and by walls adjacent to, and electrically insulated from, the target and surrounding the beam. There is at least one electron source for supplying electrons to the interior of the Faraday cage and means within the cage for blocking direct rectilinear radiation from the source to the target. The target current is measured and combined with the wall currents to provide a measurement of the ion beam current. The quantity of electrons supplied to the interior of the cage can be varied to control the target current and thereby the target surface potential. (U.K.)

  17. Doubly differential cross sections of low-energy electrons emitted in the ionization of molecular hydrogen by bare carbon ions

    International Nuclear Information System (INIS)

    Tribedi, L.C.; Richard, P.; Ling, D.; Wang, Y.D.; Lin, C.D.; Moshammer, R.; Kerby, G.W. III; Gealy, M.W.; Rudd, M.E.

    1996-01-01

    We have measured the double differential cross sections (DDCS) (d 2 σ/d var-epsilon ed Ω e ) of low-energy electron emission in the ionization of H 2 bombarded by bare carbon ions of energy 30 MeV. The energy and angular distributions of the electron DDCS have been obtained for 12 different emission angles and for electron energies varying between 0.1 and 300 eV. We have also deduced the single differential and total ionization cross section from the measured DDCS. The data have been compared with the predictions of first Born approximations and the CDW-EIS (continuum distorted wave endash eikonal initial state) model. The CDW-EIS model provides an excellent agreement with the data. copyright 1996 The American Physical Society

  18. Fragment ion and electron emission from C sub 6 sub 0 by fast heavy ion impact

    CERN Document Server

    Mizuno, T; Itoh, A; Tsuchida, H; Nakai, Y

    2003-01-01

    Correlation between electron emission and fragmentation of C sub 6 sub 0 was studied using 847keV Si sup + ions. Mass distribution of fragment ions, number distribution of secondary electrons, and final charge distribution of outgoing projectiles were successfully measured by means of a triple coincidence time-of-flight method. Strong correlation was observed for electron emission and fragmentation.

  19. Spectroscopy of highly charged tungsten ions with Electron Beam Ion Traps

    International Nuclear Information System (INIS)

    Sakaue, Hiroyuki A.; Kato, Daiji; Morita, Shigeru; Murakami, Izumi; Yamamoto, Norimasa; Ohashi, Hayato; Yatsurugi, Junji; Nakamura, Nobuyuki

    2013-01-01

    We present spectra of highly charged tungsten ions in the extreme ultra-violet (EUV) by using electron beam ion traps. The electron energy dependence of spectra is investigated of electron energies from 490 to 1440 eV. Previously unreported lines are presented in the EUV range, and some of them are identified by comparing the wavelengths with theoretical calculations. (author)

  20. EUV spectrum of highly charged tungsten ions in electron beam ion trap

    International Nuclear Information System (INIS)

    Sakaue, H.A.; Kato, D.; Murakami, I.; Nakamura, N.

    2016-01-01

    We present spectra of highly charged tungsten ions in the extreme ultra-violet (EUV) by using electron beam ion traps. The electron energy dependence of spectra was investigated for electron energy from 540 to 1370 eV. Previously unreported lines were presented in the EUV range, and comparing the wavelengths with theoretical calculations identified them. (author)

  1. Electron impact phenomena and the properties of gaseous ions

    CERN Document Server

    Field, F H; Massey, H S W; Brueckner, Keith A

    1970-01-01

    Electron Impact Phenomena and the Properties of Gaseous Ions, Revised Edition deals with data pertaining to electron impact and to molecular gaseous ionic phenomena. This book discusses electron impact phenomena in gases at low pressure that involve low-energy electrons, which result in ion formation. The text also describes the use of mass spectrometers in electron impact studies and the degree of accuracy obtained when measuring electron impact energies. This book also reviews relatively low speed electrons and the transitions that result in the ionization of the atomic system. This text the

  2. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  3. Electron capture by highly charged ions from surfaces and gases

    International Nuclear Information System (INIS)

    Allen, F.

    2008-01-01

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar 17+ and Ar 18+ ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu -1 , charge-selected and then decelerated down to 5 eVu -1 for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar 17+ and Ar 18+ ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu -1 , charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar 16+ and Xe 44+ and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  4. Ion current reduction in pinched electron beam diodes

    International Nuclear Information System (INIS)

    Quintenz, J.P.; Poukey, J.W.

    1977-01-01

    A new version of a particle-in-cell diode code has been written which permits the accurate treatment of higher-current diodes with greater physical dimensions. Using this code, we have studied ways to reduce the ion current in large-aspect-ratio pinched electron beam diodes. In particular, we find that allowing the ions to reflex in such diodes lowers the ion to electron current ratio considerably. In a 3-MV R/d=24 case this ratio was lowered by a factor of 6--8 compared with the corresponding nonreflexing-ion diode, while still producing a superpinched electron beam

  5. Convoy electron production by heavy ions in solids

    International Nuclear Information System (INIS)

    Sellin, I.A.

    1984-01-01

    The term convoy electron refers to those electrons ejected in fast ion-atom and ion-solid collisions closely matched in vector velocity to that of the incident heavy particles responsible for their ejection. Similarities and differences among electrons ejected into such states through binary electron capture to continuum and electron loss to continuum processes in single ion-atom encounters are compared and contrasted to more complex ejection processes occurring in solid targets. Puzzles posed by the apparent strong projectile Z dependence but weak emergent ion charge dependence of the yield in the case of solid targets are reviewed. Very recent progress in resolving these puzzles has been made by recent observations that the apparent mean free path for electron scattering out of the forward direction within the target is observed to be an order of magnitude greater than that for free electrons of equal velocity provided the projectile charge is high. 13 references, 2 figures, 1 table

  6. Ion-induced Auger electron spectroscopy: a new detection method for compositional homogeneities of alloyed atoms in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, A [Osaka Univ., Japan; Imura, T; Iwami, M; Kim, S C; Ushita, K; Okamoto, H; Hamakawa, Y

    1979-09-01

    Auger spectra of Si LMM transitions induced by keV Ar/sup +/ ion bombardment of Si alloy systems have been studied. The spectra observed are composed of two well-defined peaks termed elsewhere the atomic-like and bulk-like peaks, repsectively. A clear correlation has been found between the intensity of the atomic-like peak lying at 88 eV and the content of the foreign atoms alloyed with Si. Experiments were carried out on metallic silicides, or Si alloys with Au, Cu, Pd and Ni, and covalently bonded non-metallic Si alloys of C and H. From these studies, we propose that ion-induced Auger electron spectroscopy might be a useful tool for the determination of alloyed foreign atoms as well as for the study of their compositional homogeneity in binary alloy systems of silicon.

  7. Study of heliumlike neon using an electron beam ion trap

    International Nuclear Information System (INIS)

    Wargelin, B.J.; Kahn, S.M.; Beiersdorfer, P.

    1992-01-01

    The 2-to-1 spectra of several astrophysically abundant He-like ions are being studied using the Electron Beam Ion Trap (EBIT) at Lawrence Livermore National Laboratory. Spectra are recorded for a broad range of plasma parameters, including electron density, energy, and ionization balance. We describe the experimental equipment and procedure and present some typical data

  8. Atomic physics measurements in an electron Beam Ion Trap

    International Nuclear Information System (INIS)

    Marrs, R.E.; Beiersdorfer, P.; Bennett, C.

    1989-01-01

    An electron Beam Ion Trap at Lawrence Livermore National Laboratory is being used to produce and trap very-highly-charged ions (q ≤ 70/+/) for x-ray spectroscopy measurements. Recent measurements of transition energies and electron excitation cross sections for x-ray line emission are summarized. 13 refs., 10 figs

  9. Neoclassical electron heat conduction in tokamaks performed by the ions

    International Nuclear Information System (INIS)

    Ware, A.A.

    1987-07-01

    The increment to neoclassical ion heat conduction caused by electron collisions is shown to act like electron heat conduction since the energy is taken from and given back to the electrons at each diffusion step length. It can exceed electron neoclassical heat conduction by an order of magnitude

  10. Evaporative cooling of highly charged ions in EBIT [Electron Beam Ion Trap]: An experimental realization

    International Nuclear Information System (INIS)

    Schneider, M.B.; Levine, M.A.; Bennett, C.L.; Henderson, J.R.; Knapp, D.A.; Marrs, R.E.

    1988-01-01

    Both the total number and trapping lifetime of near-neon-like gold ions held in an electron beam ion trap have been greatly increased by a process of 'evaporative cooling'. A continuous flow of low-charge-state ions into the trap cools the high-charge-state ions in the trap. Preliminary experimental results using titanium ions as a coolant are presented. 8 refs., 6 figs., 2 tabs

  11. Evaluation of electon and nuclear bremsstrahlung in heavy ion collisions

    International Nuclear Information System (INIS)

    Gippner, P.

    1975-01-01

    The detection of quasimolecular X-ray continua provides the possibility of investigating the electron shells of quasimolecules transiently formed during adiabatic heavy ion-atomic collision. The contribution of the electron and nuclear bremsstrahlung to quasimolecular X-ray continua observed in bombarding various targets with 65 and 96 MeV Nb ions were estimated

  12. Incident ion charge state dependence of electron emission during slow multicharged ion-surface interactions

    International Nuclear Information System (INIS)

    Hughes, I.G.; Zeijlmans van Emmichoven, P.A.; Havener, C.C.; Overbury, S.H.; Robinson, M.T.; Zehner, D.M.; Meyer, F.W.

    1992-01-01

    Characteristic variations in the total electron yield γ as a function of crystal azimuthal orientation are reported for slow N 2+ , N 5+ and N 6+ ions incident on a Au(011) single crystal, together with measurements of γ as a function of incident ion velocity. Kinetic electron emission is shown to arise predominantly in close collisions between incident ions and target atoms, and potential electron emission is found to be essentially constant within our present velocity range. The incident ion charge state is shown to play no role in kinetic electron emission. Extremely fast neutralization times of the order of 10 - 15 secs are needed to explain the observations

  13. Ion accumulation in an electron plasma confined on magnetic surfaces

    International Nuclear Information System (INIS)

    Berkery, John W.; Marksteiner, Quinn R.; Pedersen, Thomas Sunn; Kremer, Jason P.

    2007-01-01

    Accumulation of ions can alter and may destabilize the equilibrium of an electron plasma confined on magnetic surfaces. An analysis of ion sources and ion content in the Columbia Non-neutral Torus (CNT) [T.S. Pedersen, J.P. Kremer, R.G. Lefrancois, Q. Marksteiner, N. Pomphrey, W. Reiersen, F. Dahlgreen, and X. Sarasola, Fusion Sci. Technol. 50, 372 (2006)] is presented. In CNT ions are created preferentially at locations of high electron temperature, near the outer magnetic surfaces. A volumetric integral of n e ν iz gives an ion creation rate of 2.8x10 11 ions/s. This rate of accumulation would cause neutralization of a plasma with 10 11 electrons in about half a second. This is not observed experimentally, however, because currently in CNT ions are lost through recombination on insulated rods. From a steady-state balance between the calculated ion creation and loss rates, the equilibrium ion density in a 2x10 -8 Torr neutral pressure, 7.5x10 11 m -3 electron density plasma in CNT is calculated to be n i =6.2x10 9 m -3 , or 0.8%. The ion density is experimentally measured through the measurement of the ion saturation current on a large area probe to be about 6.0x10 9 m -3 for these plasmas, which is in good agreement with the predicted value

  14. Electron Acoustic Waves in Pure Ion Plasmas

    Science.gov (United States)

    Anderegg, F.; Affolter, M.; Driscoll, C. F.; O'Neil, T. M.; Valentini, F.

    2012-10-01

    Electron Acoustic Waves (EAWs) are the low-frequency branch of near-linear Langmuir (plasma) waves: the frequency is such that the complex dielectric function (Dr, Di) has Dr= 0; and ``flattening'' of f(v) near the wave phase velocity vph gives Di=0 and eliminates Landau damping. Here, we observe standing axisymmetric EAWs in a pure ion column.footnotetextF. Anderegg, et al., Phys. Rev. Lett. 102, 095001 (2009). At low excitation amplitudes, the EAWs have vph˜1.4 v, in close agreement with near-linear theory. At moderate excitation strengths, EAW waves are observed over a range of frequencies, with 1.3 v vphvph.footnotetextF. Valentini et al., arXiv:1206.3500v1. Large amplitude EAWs have strong phase-locked harmonic content, and experiments will be compared to same-geometry simulations, and to simulations of KEENfootnotetextB. Afeyan et al., Proc. Inertial Fusion Sci. and Applications 2003, A.N.S. Monterey (2004), p. 213. waves in HEDLP geometries.

  15. Electron emission during multicharged ion-metal surface interactions

    International Nuclear Information System (INIS)

    Zeijlmans van Emmichoven, P.A.; Havener, C.C.; Hughes, I.G.; Overbury, S.H.; Robinson, M.T.; Zehner, D.M.; Meyer, F.W.

    1992-01-01

    The electron emission during multicharged ion-metal surface interactions will be discussed. The interactions lead to the emission of a significant number of electrons. Most of these electrons have energies below 30 eV. For incident ions with innershell vacancies the emission of Auger electrons that fill these vacancies has been found to occur mainly below the surface. We will present recently measured electron energy distributions which will be used to discuss the mechanisms that lead to the emission of Auger and of low-energy electrons

  16. Advances in electron cooling in heavy-ion storage rings

    International Nuclear Information System (INIS)

    Danared, H.

    1994-01-01

    The efficiency of electron cooling can be improved by reducing the temperature of the electrons. If the magnetic field at the location of the electron gun is stronger than in the region where the electrons interact with the ions, and the field gradient is adiabatic with respect to the cyclotron motion of the electrons, the resulting expansion of the electron beam reduces its transverse temperature by a factor equal to the ratio between the two fields. A ten times expanded electron beam was introduced in the CRYRING electron cooler in the summer of 1993, and similar arrangements have since then been made at the TSR ring in Heidelberg and at ASTRID in Aarhus. The reduction of the transverse electron temperature has increased cooling rates with large factors, and improves the energy resolution and increases count rates when the cooler is used as an electron target for ion-electron recombination experiments

  17. EPIC - an electron-polarized ion collider

    International Nuclear Information System (INIS)

    Cameron, J.M.

    1999-01-01

    As discussed earlier in this workshop, we have been studying at the Indiana University Cyclotron Facility (IUCF) for some time the potential of a facility-the Light Ion Spin Synchrotron (LISS)- focusing on reactions induced by polarized nucleons at ∼ 1 to 20 GeV. The technology would extrapolate from what we have learned using our existing Cooler ring using internal polarized targets. Indeed, these techniques are most viable at higher energies where the loss of the stored beam is due to the nuclear reactions which are of interest and not that of multiple Coulomb scattering which dominate in our present energy range. However, while the internal targets are not exactly fixed, they certainly do not contribute to the available energy in the center of momentum frame. Consequently, the energy and momentum which can be effective explored are 6 GeV and 3 GeV/c respectively, about the same range that we expect to explore using electromagnetic probes using the enhanced Thomas Jefferson National Accelerator Laboratory electron beam. Looking at the structure of hadrons, as we currently understand it, one can divide it into four size scales. The LISS facility would permit studies of the manifestation of the nucleon substructure but generally would not get to scales where one would only have incoherent interactions at the partonic level. Following in a path already trodden by our European colleagues, we have recently started to look at the possibility of adding an electronic collider option to our plans. This would significantly increase the kinematic range, with 25 GeV protons and 4 GeV electrons (one gets over 20 GeV in the center of mass-equivalent to about 200 GeV on a fixed proton target). The accessible range provides coverage up to Q 2 = 20 GeV/ c 2 and down to x ∼ 10 -2 (here x = Q 2 /2Mv, the usual Bjorken scaling variable). As the energy of both beams would be variable, one can cover the whole range between HERMES and CERN/FNAL muon beams. Examples of the range of

  18. Transport of secondary electrons and reactive species in ion tracks

    Science.gov (United States)

    Surdutovich, Eugene; Solov'yov, Andrey V.

    2015-08-01

    The transport of reactive species brought about by ions traversing tissue-like medium is analysed analytically. Secondary electrons ejected by ions are capable of ionizing other molecules; the transport of these generations of electrons is studied using the random walk approximation until these electrons remain ballistic. Then, the distribution of solvated electrons produced as a result of interaction of low-energy electrons with water molecules is obtained. The radial distribution of energy loss by ions and secondary electrons to the medium yields the initial radial dose distribution, which can be used as initial conditions for the predicted shock waves. The formation, diffusion, and chemical evolution of hydroxyl radicals in liquid water are studied as well. COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy.

  19. Investigation of instability of M23C6 particles in F82H steel under electron and ion irradiation conditions

    Science.gov (United States)

    Kano, Sho; Yang, Huilong; Shen, Jingjie; Zhao, Zishou; McGrady, John; Hamaguchi, Dai; Ando, Mamami; Tanigawa, Hiroyasu; Abe, Hiroaki

    2018-04-01

    In order to clarify the instability of M23C6 in F82H steel under irradiation, both electron irradiation using a high voltage electron microscope (HVEM) and ion irradiation using an ion accelerator were performed. For the electron irradiation, in-situ observation under 2 MV electron irradiation and ex-situ high resolution electron microscopic (HREM) analysis were utilized to evaluate the response of M23C6 against irradiation. The temperature dependence of the irradiation induced instability of the carbide was first confirmed: 293 K indicating severe loss of crystallinity due to dissolution of the constituent atoms though irradiation-enhanced diffusion under the vacancy diffusion by the focused electron beam irradiation. For the ion irradiation, 10.5 MeV-Fe3+ ion was applied to bombard the F82H steel at 673 K to achieve the displacement damage of ≈20 dpa at the depth of 1.0 μm from surface. Cross-section TEM specimens were prepared by a focused ion beam technique. The shrinkage of carbide particles was observed especially near the irradiation surface. Besides, the lattice fringes at the periphery of carbide were observed in the irradiated M23C6 by the HREM analysis, which is different from that observed in the electron irradiation. It was clarified that the instability of M23C6 is dependent on the irradiation conditions, indicating that the flow rate of vacancy type defects might be the key factor to cause the dissolution of constituent atoms of carbide particles into matrix under irradiation.

  20. Collisional transfer of electrons to the continuum of atomic and molecular ions

    International Nuclear Information System (INIS)

    Gonzalez Lepera, C.E.

    1983-01-01

    The aim of this study was the systematic investigation of the differences that appear in the peaks of distribution of doubly differential (in angle an energy) 'convoy' electrons, when comparing spectra obtained by bombarding thin carbon foils with atomic (H + ) and molecular (H 2 + ) projectiles of equal velocity. The measurements show that the production yield of such electrons is inversely propotional to the ion dwell time in the solid. For long times, the yield ratio fluctuates around the unity value, and the amplitude of this dispersion decreases for longer times. A higher yield is measured for (H 2 + ), but only near the peak cusp. The double differential cross section (DDCS) for electron capture is calculated in second order Born approximation. A transition from a 1s state to the continuum of two correlated protons as a function of their internuclear distance R is considered. As R decreases from approx. 0.5 atomic units towards zero, the DDCS value increases from that corresponding to the atomic projectil (Z=1) limit to the united atom value (Z=2). It is found that, the higher the projectil velocity, the better is the DDCS value agreement with both limits. The equipment used by the author is described. (M.E.L.) [es

  1. Numerical simulation methods for electron and ion optics

    International Nuclear Information System (INIS)

    Munro, Eric

    2011-01-01

    This paper summarizes currently used techniques for simulation and computer-aided design in electron and ion beam optics. Topics covered include: field computation, methods for computing optical properties (including Paraxial Rays and Aberration Integrals, Differential Algebra and Direct Ray Tracing), simulation of Coulomb interactions, space charge effects in electron and ion sources, tolerancing, wave optical simulations and optimization. Simulation examples are presented for multipole aberration correctors, Wien filter monochromators, imaging energy filters, magnetic prisms, general curved axis systems and electron mirrors.

  2. Ion beam neutralization with ferroelectrically generated electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Herleb, U; Riege, H [European Organization for Nuclear Research, Geneva (Switzerland). LHC Division

    1997-12-31

    A technique for ion beam space-charge neutralization with pulsed electron beams is described. The intensity of multiply-charged ions produced with a laser ion source can be enhanced or decreased separately with electron beam trains of MHz repetition rate. These are generated with ferroelectric cathodes, which are pulsed in synchronization with the laser ion source. The pulsed electron beams guide the ion beam in a similar way to the alternating gradient focusing of charged particle beams in circular accelerators such as synchrotrons. This new neutralization technology overcomes the Langmuir-Child space-charge limit and may in future allow ion beam currents to be transported with intensities by orders of magnitude higher than those which can be accelerated today in a single vacuum tube. (author). 6 figs., 10 refs.

  3. PIC simulation of the electron-ion collision effects on suprathermal electrons

    International Nuclear Information System (INIS)

    Wu Yanqing; Han Shensheng

    2000-01-01

    The generation and transportation of suprathermal electrons are important to both traditional ICF scheme and 'Fast Ignition' scheme. The author discusses the effects of electron-ion collision on the generation and transportation of the suprathermal electrons by parametric instability. It indicates that the weak electron-ion term in the PIC simulation results in the enhancement of the collisional absorption and increase of the hot electron temperature and reduction in the maximum electrostatic field amplitude while wave breaking. Therefore the energy and distribution of the suprathermal electrons are changed. They are distributed more close to the phase velocity of the electrostatic wave than the case without electron-ion collision term. The electron-ion collision enhances the self-consistent field and impedes the suprathermal electron transportation. These factors also reduce the suprathermal electron energy. In addition, the authors discuss the effect of initial condition on PIC simulation to ensure that the results are correct

  4. Anomalous behavior in temporal evolution of ripple wavelength under medium energy Ar{sup +}-ion bombardment on Si: A case of initial wavelength selection

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Sandeep Kumar [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India); Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Cuerno, Rodolfo [Departamento de Matematicas and Grupo Interdisciplinar de Sistemas Complejos (GISC), Universidad Carlos III de Madrid, 28911 Leganes (Spain); Kanjilal, Dinakar [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Som, Tapobrata, E-mail: tsom@iopb.res.in [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India)

    2016-06-14

    We have studied the early stage dynamics of ripple patterns on Si surfaces, in the fluence range of 1–3 × 10{sup 18} ions cm{sup −2}, as induced by medium energy Ar{sup +}-ion irradiation at room temperature. Under our experimental conditions, the ripple evolution is found to be in the linear regime, while a clear decreasing trend in the ripple wavelength is observed up to a certain time (fluence). Numerical simulations of a continuum model of ion-sputtered surfaces suggest that this anomalous behavior is due to the relaxation of the surface features of the experimental pristine surface during the initial stage of pattern formation. The observation of this hitherto unobserved behavior of the ripple wavelength seems to have been enabled by the use of medium energy ions, where the ripple wavelengths are found to be order(s) of magnitude larger than those at lower ion energies.

  5. Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions.

    Energy Technology Data Exchange (ETDEWEB)

    Siekhaus, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Teslich, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-23

    Depleted uranium that included carbide inclusions was sputtered with 30-keV gallium ions or 16-kev cesium ions to depths much greater than the ions’ range, i.e. using steady-state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady-state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U₈₆Ga₁₄, (UC)₇₀Ga₃₀ and U₈₁Cs₉, (UC)₇₉Cs₂₁, respectively.

  6. Kinetic theory for electron dynamics near a positive ion

    International Nuclear Information System (INIS)

    Wrighton, Jeffrey M; Dufty, James W

    2008-01-01

    A theoretical description of time correlation functions for electron properties in the presence of a positive ion of charge number Z is given. The simplest case of an electron gas distorted by a single ion is considered. A semi-classical representation with a regularized electron–ion potential is used to obtain a linear kinetic theory that is asymptotically exact at short times. This Markovian approximation includes all initial (equilibrium) electron–electron and electron–ion correlations through renormalized pair potentials. The kinetic theory is solved in terms of single-particle trajectories of the electron–ion potential and a dielectric function for the inhomogeneous electron gas. The results are illustrated by a calculation of the autocorrelation function for the electron field at the ion. The dependence on charge number Z is shown to be dominated by the bound states of the effective electron–ion potential. On this basis, a very simple practical representation of the trajectories is proposed and shown to be accurate over a wide range including strong electron–ion coupling. This simple representation is then used for a brief analysis of the dielectric function for the inhomogeneous electron gas

  7. Dust ion-acoustic shock waves in magnetized pair-ion plasma with kappa distributed electrons

    Science.gov (United States)

    Kaur, B.; Singh, M.; Saini, N. S.

    2018-01-01

    We have performed a theoretical and numerical analysis of the three dimensional dynamics of nonlinear dust ion-acoustic shock waves (DIASWs) in a magnetized plasma, consisting of positive and negative ion fluids, kappa distributed electrons, immobile dust particulates along with positive and negative ion kinematic viscosity. By employing the reductive perturbation technique, we have derived the nonlinear Zakharov-Kuznetsov-Burgers (ZKB) equation, in which the nonlinear forces are balanced by dissipative forces (associated with kinematic viscosity). It is observed that the characteristics of DIASWs are significantly affected by superthermality of electrons, magnetic field strength, direction cosines, dust concentration, positive to negative ions mass ratio and viscosity of positive and negative ions.

  8. TARGET EXCITATION IN BARE ION XE/AR COLLISIONS STUDIED BY ELECTRON TARGET ION COINCIDENCES

    NARCIS (Netherlands)

    DENIJS, G; HOEKSTRA, R; MORGENSTERN, R

    We present electron spectra resulting from collisions of bare ions N-15(7+) and C-13(6+) on Ar and the charge state distribution of target ions resulting from C-13(6+)-Xe collisions. From both type of experiments we find evidence that electron capture accompanied by target excitation is an important

  9. Many-electron phenomena in the ionization of ions

    International Nuclear Information System (INIS)

    Mueller, A.

    2004-01-01

    Full text: Single and multiple ionization in ion-atom collisions involve a multitude of complex interactions between the electrons and nuclei of projectile and target. Some of the complexity is avoided in studies of fast collisions when the impulse approximation can be applied and the electrons can be described as independent quasi-free particles with a known momentum distribution. For the detailed investigation of ionization mechanisms that can occur in fast ion-atom collisions, it is illuminating to consider collisions of ions (or atoms) and really free electrons with a narrow energy spread. High energy resolution in electron-ion collision studies provides access to individual, possibly even state-selective, reaction pathways. Even in the simple electron-ion collision system (simple compared with the initial ion-atom problem) single and multiple ionization still involve a multitude of complex mechanisms. Besides the direct removal of one or several electrons from the target by electron impact, resonant and non-resonant formation of intermediate multiply excited states which subsequently decay by electron emission is important in single and multiple ionization of ions and atoms. Direct ionization proceeds via one-step or multi-step knock-off mechanisms which can partly be disentangled by studying effects of different projectile species. The role of multiply excited states in the ionization can be experimentally studied in great detail by a further reduction of the initial ion-atom problem. Multiply excited states of atoms and ions can be selectively populated by photon-ion interactions making use of the potential for extreme energy resolution made available at modern synchrotron radiation sources. In the review talk, examples of studies on single and multiple ionization in electron-ion collisions will be discussed in some detail. Electron-ion collision experiments will also be compared with photon-ion interaction studies. Many-electron phenomena have been observed

  10. Atomic physics of highly charged ions in an electron beam ion trap

    International Nuclear Information System (INIS)

    Marrs, R.E.

    1990-07-01

    Two electron beam ion traps are in use at LLNL for the purpose of studying the properties of very highly charged ions and their interactions with electrons. This paper reviews the operation of the traps and discusses recent experiments in three areas: precision transition energy measurements in the limit of very high ion charge, dielectronic recombination measurements for the He-like isoelectronic sequence, and measurements of x-ray polarization. 22 refs., 11 figs., 1 tab

  11. Gaseous odd- and even-electron ions

    International Nuclear Information System (INIS)

    Wagner, W.; Heimbach, H.; Levsen, K.

    1980-01-01

    The principal collision-induced fragmentations of simple protonated ketones, aldehydes, ethers, amines, sulphides, alcohols, acids, nitriles and halides are discussed. These protonated molecules decompose mainly by loss of alkane, alkene and RX (R = alkyl, H; X = OH, SH, NH 2 , Br, I). Substantial radical losses are only observed for small protonated molecules. Deuterium-labelling demonstrates that the X-H bond is particularly strong. The fragmentation of (MH) + ions is compared with that of the corresponding (M) + sup(.) ions is compared with that of the corresponding (M) + sup(.) ions. The spectra of the (M) + sup(.) ions are dominated by direct bond cleavages, in particular α-cleavages, as a result of both the stability of the ionic fragment and the loose transition state. In (MH) + ions direct bond cleavages lead to energetically less favourable products. Thus rearrangement reactions play a more important role in the decomposition of these ions. (MH) + ions are more stable relative to fragmentation than (M) + sup(.) ions. (orig.)

  12. A simple photoionization scheme for characterizing electron and ion spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Wituschek, A.; Vangerow, J. von; Grzesiak, J.; Stienkemeier, F.; Mudrich, M., E-mail: mudrich@physik.uni-freiburg.de [Physikalisches Institut, Universität Freiburg, 79104 Freiburg (Germany)

    2016-08-15

    We present a simple diode laser-based photoionization scheme for generating electrons and ions with well-defined spatial and energetic (≲2 eV) structures. This scheme can easily be implemented in ion or electron imaging spectrometers for the purpose of off-line characterization and calibration. The low laser power ∼1 mW needed from a passively stabilized diode laser and the low flux of potassium atoms in an effusive beam make our scheme a versatile source of ions and electrons for applications in research and education.

  13. Electron-ion recombination rates for merged-beams experiments

    International Nuclear Information System (INIS)

    Pajek, M.

    1994-01-01

    Energy dependence of the electron-ion recombination rates are studied for different recombination processes (radiative recombination, three-body recombination, dissociative recombination) for Maxwellian relative velocity distribution of arbitrary asymmetry. The results are discussed in context of the electron-ion merged beams experiments in cooling ion storage rings. The question of indication of a possible contribution of the three-body recombination to the measured recombination rates versus relative energy is particularly addressed. Its influence on the electron beam temperature derived from the energy dependence of recombination rate is discussed

  14. Energy dependence of Lα-to-Ll x-ray intensity ratios for Yb and Pb produced by heavy-ion bombardment

    International Nuclear Information System (INIS)

    Gray, T.J.

    1980-01-01

    Measurements of the incident-ion energy dependence of Lα-to-Ll x-ray intensity ratios are reported for protons incident at 0.40 to 2.20 MeV/amu on thin targets of Pb and for 4 He and C ions incident upon Yb. The data are compared to calculations of the Lα-to-Ll ratio which include the effects of alignment of the 2p/sub 3/2/ state of the target

  15. Ion- and electron-acoustic solitons in two-electron temperature space plasmas

    International Nuclear Information System (INIS)

    Lakhina, G. S.; Kakad, A. P.; Singh, S. V.; Verheest, F.

    2008-01-01

    Properties of ion- and electron-acoustic solitons are investigated in an unmagnetized multicomponent plasma system consisting of cold and hot electrons and hot ions using the Sagdeev pseudopotential technique. The analysis is based on fluid equations and the Poisson equation. Solitary wave solutions are found when the Mach numbers exceed some critical values. The critical Mach numbers for the ion-acoustic solitons are found to be smaller than those for electron-acoustic solitons for a given set of plasma parameters. The critical Mach numbers of ion-acoustic solitons increase with the increase of hot electron temperature and the decrease of cold electron density. On the other hand, the critical Mach numbers of electron-acoustic solitons increase with the increase of the cold electron density as well as the hot electron temperature. The ion-acoustic solitons have positive potentials for the parameters considered. However, the electron-acoustic solitons have positive or negative potentials depending whether the fractional cold electron density with respect to the ion density is greater or less than a certain critical value. Further, the amplitudes of both the ion- and electron-acoustic solitons increase with the increase of the hot electron temperature. Possible application of this model to electrostatic solitary waves observed on the auroral field lines by the Viking spacecraft is discussed

  16. The repetitive flaking of Inconel 625 by 100 keV helium bombardment

    International Nuclear Information System (INIS)

    Whitton, J.L.; Chen, H.M.; Littmark, U.

    1981-01-01

    Repetitive flaking of Inconel 625 occurs with ion bombardment doses of > than 10 18 100 keV helium ions cm -2 , with up to 39 exfoliations being observed after bombardment with 3 x 10 19 ions cm -2 . The thickness of the flakes, measured by scanning electron microscopy, is some 30% greater than when measured by Rutherford backscattering (RBS) of 1.8 MeV helium ions. These RBS measurements compare well with the thickness of the remaining layers in the resultant craters and to the most probable range of the 100 keV helium. The area of the flakes is dictated by the grain boundaries, and when one flake is ejected, the adjacent grains are prevented from doing so since there now exists an escape route for the injected helium. A strong dose rate dependence is observed; decreasing the beam current from 640 μA cm -2 to 64 μA cm -2 results in a factor 20 fewer flakes being exfoliated (for the same total dose of 3 x 10 19 ions cm -2 ). Successive flakes decrease in area, suggesting that eventually a cratered, but stable, surface will result with the only erosion being by the much less effective mechanism of sputtering. (orig.)

  17. Ion collection efficiency of ionization chambers in electron beams

    International Nuclear Information System (INIS)

    Garcia, S.; Cecatti, E.R.

    1984-01-01

    When ionization chambers are used in pulsed radiation beams the high-density of ions produced per pulse permits ion recombination, demanding the use of a correction factor. An experimental technique using the charge collected at two different voltages permits the calculation of the ion collection efficiency. The ion collection efficiency of some common ionization chambers in pulsed electron beams were studied as a function of electron energy, dose rate and depth. Accelerators with magnetic scanning system, in which the instantaneous dose rate is much greater than the average dose rate, present a smaller collection efficiency than accelerators with scattering foil. The results lead to the introduction of a correction factor for ion recombination that is the reciprocal of the ion collection efficiency. It is also suggested a simple technique to connect an external variable DC power supply in a Baldwin Farmer dosemeter. (Author) [pt

  18. A review of transmission electron microscopes with in situ ion irradiation

    Science.gov (United States)

    Hinks, J. A.

    2009-12-01

    Transmission electron microscopy (TEM) with in situ ion irradiation is unique amongst experimental techniques in allowing the direct observation of the internal microstructure of materials on the nanoscale whilst they are being subjected to bombardment with energetic particles. Invaluable insights into the underlying atomistic processes at work can be gained through direct investigation of radiation induced and enhanced effects such as: phase changes and segregation; mechanical and structural changes; atomic/layer mixing and chemical disorder; compositional changes; chemical reactions; grain growth and shrinkage; precipitation and dissolution; defect/bubble formation, growth, motion, coalescence, removal and destruction; ionisation; diffusion; and collision cascades. The experimental results obtained can be used to validate the predictions of computational models which in turn can elucidate the mechanisms behind the phenomena seen in the microscope. It is 50 years since the first TEM observations of in situ ion irradiation were made by D.W. Pashley, A.E.B. Presland and J.W. Menter at the Tube Investment Laboratories in Cambridge, United Kingdom and 40 years since the first interfacing of an ion beam system with a TEM by P.A. Thackery, R.S. Nelson and H.C. Sansom at the Atomic Energy Research Establishment at Harwell, United Kingdom. In that time the field has grown with references in the literature to around thirty examples of such facilities. This paper gives an overview of the importance of the technique, especially with regard to the current challenges faced in understanding radiation damage in nuclear environments; a description of some of the important construction elements and design considerations of TEMs with in situ ion irradiation; a brief history of the development of this type of instrument; a summary of the facilities built around the world over the last half century; and finally a focus on the instruments in operation today.

  19. Status report on electron cyclotron resonance ion sources at the Heavy Ion Medical Accelerator in Chiba

    CERN Document Server

    Kitagawa, A; Sekiguchi, M; Yamada, S; Jincho, K; Okada, T; Yamamoto, M; Hattori, T G; Biri, S; Baskaran, R; Sakata, T; Sawada, K; Uno, K

    2000-01-01

    The Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences (NIRS) is not only dedicated to cancer therapy, it is also utilized with various ion species for basic experiments of biomedical science, physics, chemistry, etc. Two electron cyclotron resonance (ECR) ion sources are installed for production of gaseous ions. One of them, the NIRS-ECR, is a 10 GHz ECR ion source, and is mainly operated to produce C/sup 4+/ ions for daily clinical treatment. This source realizes good reproducibility and reliability and it is easily operated. The other source, the NIRS-HEC, is an 18 GHz ECR ion source that is expected to produce heavier ion species. The output ion currents of the NIRS-ECR and the NIRS-HEC are 430e mu A for C/sup 4+/ and 1.1e mA for Ar/sup 8+/, respectively. (14 refs).

  20. Axial ion-electron emission microscopy of IC radiation hardness

    Science.gov (United States)

    Doyle, B. L.; Vizkelethy, G.; Walsh, D. S.; Swenson, D.

    2002-05-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff-Pelletron to velocities of 1.9 MeV/amu. The electronic stopping power for heavy ions is near a maximum at this velocity, and their range is ˜20 μm in Si. These ions therefore represent the most ionizing form of radiation in nature, and are nearly ideal for performing single event effects testing of integrated circuits. Unfortunately, the energy definition of the RFQ-boosted ions is rather poor (˜ a few %), which makes problematic the focussing of such ions to the submicron spots required for REM. To circumvent this problem, we have invented ion electron emission microscopy (IEEM). One can perform REM with the IEEM system without focussing or scanning the ion beam. This is because the position on the sample where each ion strikes is determined by projecting ion-induced secondary electrons at high magnification onto a single electron position sensitive detector. This position signal is then correlated with each REM event. The IEEM system is now mounted along the beam line in an axial geometry so that the ions pass right through the electron detector (which is annular), and all of the electrostatic lenses used for projection. The beam then strikes the sample at normal incidence which results in maximum ion penetration and removes a parallax problem experienced in an earlier system. Details of both the RFQ-booster and the new axial IEEM system are given together with some of the initial results of performing REM on Sandia-manufactured radiation hardened integrated circuits.

  1. MD and BCA simulations of He and H bombardment of fuzz in bcc elements

    Science.gov (United States)

    Klaver, T. P. C.; Zhang, S.; Nordlund, K.

    2017-08-01

    We present results of MD simulations of low energy He ion bombardment of low density fuzz in bcc elements. He ions can penetrate several micrometers into sparse fuzz, which allows for a sufficient He flux through it to grow the fuzz further. He kinetic energy falls off exponentially with penetration depth. A BCA code was used to carry out the same ion bombardment on the same fuzz structures as in MD simulations, but with simpler, 10 million times faster calculations. Despite the poor theoretical basis of the BCA at low ion energies, and the use of somewhat different potentials in MD and BCA calculations, the ion penetration depths predicted by BCA are only ∼12% less than those predicted by MD. The MD-BCA differences are highly systematic and trends in the results of the two methods are very similar. We have carried out more than 200 BCA calculation runs of ion bombardment of fuzz, in which parameters in the ion bombardment process were varied. For most parameters, the results show that the ion bombardment process is quite generic. The ion species (He or H), ion mass, fuzz element (W, Ta, Mo, Fe) and fuzz element lattice parameter turned out to have a modest influence on ion penetration depths at most. An off-normal angle of incidence strongly reduces the ion penetration depth. Increasing the ion energy increases the ion penetration, but the rate by which ion energy drops off at high ion energies follows the same exponential pattern as at lower energies.

  2. Ion Implantation Processing Technologies for Telecommunications Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, T E

    2000-05-01

    The subject CRADA was a collaboration between Oak Ridge National Laboratory and Bell Laboratories, Lucent Technologies (formerly AT and T Bell Laboratories) to explore the development of ion implantation technologies for silicon integrated circuit (IC) manufacturing.

  3. Advanced ion beam analysis of materials using ion-induced fast electron

    Energy Technology Data Exchange (ETDEWEB)

    Kudo, Hiroshi; Tanabe, Atsushi; Ishihara, Toyoyuki [Tsukuba Univ., Ibaraki (Japan); and others

    1997-03-01

    Recent progress in the study of high-energy shadowing effect using ion-induced electron spectroscopy is reported with emphasis on a possibility of determination of local electronic structure in solids, which has been a difficult problem to approach with other experimental techniques. We demonstrate real-space determination of covalent-bond electron distribution in Si crystal. The analysis technique may provide a new field of ion beam analysis of solids. (author)

  4. Dissociative recombination of interstellar ions: electronic structure calculations for HCO+

    International Nuclear Information System (INIS)

    Kraemer, W.P.; Hazi, A.U.

    1985-01-01

    The present study of the interstellar formyl ion HCO + is the first attempt to investigate dissociative recombination for a triatomic molecular ion using an entirely theoretical approach. We describe a number of fairly extensive electronic structure calculations that were performed to determine the reaction mechanism of the e-HCO + process. Similar calculations for the isoelectronic ions HOC + and HN 2 + are in progress. 60 refs

  5. Electron-Ion Beam Coupling Through Collective Interactions

    National Research Council Canada - National Science Library

    Wheelock, Adrian; Cooke, David L; Gatsonis, Nikolaos A

    2006-01-01

    .... It is shown that Coulomb collisions, which can act to match velocities through strong ion-electron collisions between particles with low relative velocities, are far too slow to explain the phenomenon...

  6. Analytic theory of the spherical electron to ion convertor

    International Nuclear Information System (INIS)

    Verdeyen, J.T.; Miller, P.A.

    1980-01-01

    Calculations will be presented which indicate that one could, with high efficiency, convert the electron beam energy transported from many pinched diode to ions at a reasonably sized evacuated spherical shell - or a light bulb

  7. Nonplanar ion acoustic waves with kappa-distributed electrons

    International Nuclear Information System (INIS)

    Sahu, Biswajit

    2011-01-01

    Using the standard reductive perturbation technique, nonlinear cylindrical and spherical Kadomtsev-Petviashvili equations are derived for the propagation of ion acoustic solitary waves in an unmagnetized collisionless plasma with kappa distributed electrons and warm ions. The influence of kappa-distributed electrons and the effects caused by the transverse perturbation on cylindrical and spherical ion acoustic waves (IAWs) are investigated. It is observed that increase in the kappa distributed electrons (i.e., decreasing κ) decreases the amplitude of the solitary electrostatic potential structures. The numerical results are presented to understand the formation of ion acoustic solitary waves with kappa-distributed electrons in nonplanar geometry. The present investigation may have relevance in the study of propagation of IAWs in space and laboratory plasmas.

  8. Structural and electronic properties of ion-implanted superconductors

    International Nuclear Information System (INIS)

    Bernas, H.; Nedellec, P.

    1980-01-01

    Recent work on ion implanted superconductors is reviewed. In situ x-ray, channeling, resistivity, and electron tunneling experiments now approach the relation between lattice order (or disorder) and superconductivity

  9. Sensitivity of Electron Transfer Mediated Decay to Ion Pairing.

    Science.gov (United States)

    Pohl, Marvin N; Richter, Clemens; Lugovoy, Evgeny; Seidel, Robert; Slavíček, Petr; Aziz, Emad F; Abel, Bernd; Winter, Bernd; Hergenhahn, Uwe

    2017-08-17

    Ion pairing in electrolyte solutions remains a topic of discussion despite a long history of research. Very recently, nearest-neighbor mediated electronic de-excitation processes of core hole vacancies (electron transfer mediated decay, ETMD) were proposed to carry a spectral fingerprint of local solvation structure and in particular of contact ion pairs. Here, for the first time, we apply electron-electron coincidence detection to a liquid microjet, and record ETMD spectra of Li 1s vacancies in aqueous solutions of lithium chloride (LiCl) in direct comparison to lithium acetate (LiOAc). A change in the ETMD spectrum dependent on the electrolyte anion identity is observed for 4.5 M salt concentration. We discuss these findings within the framework of the formation and presence of contact ion pairs and the unique sensitivity of ETMD spectroscopy to ion pairing.

  10. Electron-impact ionization of heavy atomic ions

    International Nuclear Information System (INIS)

    Pindzola, M.S.; Griffin, D.C.; Bottcher, C.

    1987-01-01

    General theoretical methods for the calculation of direct and indirect processes in the electron-impact ionization of heavy atomic ions are reviewed. Cross section results for Xe 8+ and U 89+ are presented. 12 refs., 4 figs

  11. Sawtooth activity of the ion cloud in an electron-beam ion trap

    International Nuclear Information System (INIS)

    Radtke, R.; Biedermann, C.

    2003-01-01

    The dynamics of an ensemble of highly charged Ar and Ba ions in an electron-beam ion trap (EBIT) was studied by recording time-resolved x-ray spectra emitted from trapped ions. Sawtoothlike signatures manifest in the spectra for a variety of EBIT operating conditions indicating a sudden collapse of the ion inventory in the trap. The collapse occurs on a time scale of approximately 100 ms and the evolution of the sawteeth is very sensitive to parameters such as electron-beam current and axial trap depth. Analysis of the measurements is based on a time-dependent calculation of the trapping process showing that sawtooth activity is caused by the feedback between the low-Z argon and high-Z barium ions. This unexpected behavior demonstrates the importance of nonlinear effects in electron-beam traps containing more than a single ion species

  12. Electron spin resonance investigations on polycarbonate irradiated with U ions

    Energy Technology Data Exchange (ETDEWEB)

    Chipara, M.I.; Reyes-Romero, J

    2001-12-01

    Electron spin resonance investigations on polycarbonate irradiated with uranium ions are reported. The dependence of the resonance line parameters (line intensity, line width, double integral) on penetration depth and dose is studied. The nature of free radicals induced in polycarbonate by the incident ions is discussed in relation with the track structure. The presence of severe exchange interactions among free radicals is noticed.

  13. Collective ion acceleration by relativistic electron beams in plasmas

    International Nuclear Information System (INIS)

    Galvez, M.; Gisler, G.

    1991-01-01

    A two-dimensional fully electromagnetic particle-in-cell code is used to simulate the interaction of a relativistic electron beam injected into a finite-size background neutral plasma. The simulations show that the background electrons are pushed away from the beam path, forming a neutralizing ion channel. Soon after the beam head leaves the plasma, a virtual cathode forms which travels away with the beam. However, at later times a second, quasi-stationary, virtual cathode forms. Its position and strength depends critically on the parameters of the system which critically determines the efficiency of the ion acceleration process. The background ions trapped in the electrostatic well of the virtual cathode are accelerated and at later times, the ions as well as the virtual cathode drift away from the plasma region. The surfing of the ions in the electrostatic well produces an ion population with energies several times the initial electron beam energy. It is found that optimum ion acceleration occurs when the beam-to-plasma density ratio is near unity. When the plasma is dense, the beam is a weak perturbation and accelerates few ions, while when the plasma is tenuous, the beam is not effectively neutralized, and a virtual cathode occurs right at the injection plane. The simulations also show that, at the virtual cathode position, the electron beam is pinched producing a self-focusing phenomena

  14. Free-electron lasers with magnetized ion-wiggler

    International Nuclear Information System (INIS)

    Mehdian, H.; Jafari, S.; Hasanbeigi, A.; Ebrahimi, F.

    2009-01-01

    Significant progress has been made using laser ionized channels to guide electron beams in the ion focus regime in a free-electron laser. Propagation of an electron beam in the ion focusing regime (IFR) allows the beam to propagate without expanding from space-charge repulsion. The ninth-degree polynomial dispersion relation for electromagnetic and space-charge waves is derived analytically by solving the electron momentum transfer and wave equations. The variation of resonant frequencies and peak growth rates with axial magnetic field strength has been demonstrated. Substantial enhancement in peak growth rate is obtained as the axial field frequency approaches the gyroresonance frequency.

  15. Delta-electron emission in fast heavy ion atom collisions

    International Nuclear Information System (INIS)

    Schmidt-Boecking, H.; Ramm, U.; Berg, H.; Kelbch, C.; Feng Jiazhen; Hagmann, S.; Kraft, G.; Ullrich, J.

    1991-01-01

    The δ-electron emission processes occuring in fast heavy ion atom collisons are explained qualitatively. The different spectral structures of electron emission arising from either the target or the projectile are explained in terms of simple models of the kinetics of momentum transfer induced by the COULOMB forces. In collisions of very heavy ions with matter, high nuclear COULOMB forces are created. These forces lead to a strong polarization of the electronic states of the participated electrons. The effects of this polarization are discussed. (orig.)

  16. Electrons with continuous energy distribution from energetic heavy ion collisions

    International Nuclear Information System (INIS)

    Berenyi, D.

    1984-01-01

    The properties and origin of continuous electron spectrum emitted in high energy heavy ion collisions are reviewed. The basic processes causing the characteristic regions of the continuous spectrum are described. The contribution of electrons ejected from the target and from the projectile are investigated in detail in the cases of light and heavy projectiles. The recently recognized mechanisms, electron-capture-to-continuum (ECC) and electron-loss-to-continuum (ELC), leading to a cusp in forward direction, and their theoretical interpretations are discussed. The importance of data from ion-atom collisions in the field of atomic physics and in applications are briefly summarized. (D.Gy)

  17. Multiple-electron processes in fast ion-atom collisions

    International Nuclear Information System (INIS)

    Schlachter, A.S.

    1989-03-01

    Research in atomic physics at the Lawrence Berkeley Laboratory Super-HILAC and Bevalac accelerators on multiple-electron processes in fast ion-atom collisions is described. Experiments have studied various aspects of the charge-transfer, ionization, and excitation processes. Examples of processes in which electron correlation plays a role are resonant transfer and excitation and Auger-electron emission. Processes in which electron behavior can generally be described as uncorrelated include ionization and charge transfer in high-energy ion-atom collisions. A variety of experiments and results for energies from 1 MeV/u to 420 MeV/u are presented. 20 refs., 15 figs

  18. Electronic excitations in fast ion-solid collisions

    International Nuclear Information System (INIS)

    Burgdoerfer, J.

    1990-01-01

    We review recent developments in the study of electronic excitation of projectiles in fast ion-solid collisions. Our focus will be primarily on theory but experimental advances will also be discussed. Topics include the evidence for velocity-dependent thresholds for the existence of bound states, wake-field effects on excited states, the electronic excitation of channeled projectiles, transport phenomena, and the interaction of highly charged ions with surfaces. 44 refs., 14 figs

  19. Electronic structure of incident carbon ions on a graphite surface

    International Nuclear Information System (INIS)

    Kiuchi, Masato; Takeuchi, Takae; Yamamoto, Masao.

    1997-01-01

    The electronic structure of an incident carbon ion on a graphite surface is discussed on the basis of ab initio molecular orbital calculations. A carbon cation forms a covalent bond with the graphite, and a carbon nonion is attracted to the graphite surface through van der Waals interaction. A carbon anion has no stable state on a graphite surface. The charge effects of incident ions become clear upon detailed examination of the electronic structure. (author)

  20. Distributions of the ion temperature, ion pressure, and electron density over the current sheet surface

    Energy Technology Data Exchange (ETDEWEB)

    Kyrie, N. P., E-mail: kyrie@fpl.gpi.ru; Markov, V. S., E-mail: natalya.kyrie@yandex.ru; Frank, A. G.; Vasilkov, D. G.; Voronova, E. V. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2016-06-15

    The distributions of the ion temperature, ion pressure, and electron density over the width (the major transverse dimension) of the current sheet have been studied for the first time. The current sheets were formed in discharges in argon and helium in 2D and 3D magnetic configurations. It is found that the temperature of argon ions in both 2D and 3D magnetic configurations is almost uniform over the sheet width and that argon ions are accelerated by the Ampère force. In contrast, the distributions of the electron density and the temperature of helium ions are found to be substantially nonuniform. As a result, in the 2D magnetic configuration, the ion pressure gradient across the sheet width makes a significant contribution (comparable with the Ampère force) to the acceleration of helium ions, whereas in the 3D magnetic configuration, the Ampère force is counterbalanced by the pressure gradient.